TeaTime

When you select the Exterior Room, ALDO shows the "Rooms" layer selected, so that is it's layer.
 
What exactly for?

Ooo fun challenge!!

Started with a basic U-Shaped stair, 0" gap.
Open it and on the General panel set Tread Depth to Lock Number, uncheck Automatic Height.
On the Style panel uncheck Allow Wrap, this is important, otherwise you can't have stairs side-by-side like you'll need.
Copy that lower section next to the original (I'd suggest Copy/Paste, Point to Point Move).
Open the copy, make sure Lock Top is set then change the tread depth to twice the original (ex: if the original is 11" set them to 22"), and the tread count to 1/2 the original minus 1 (in my example there were 8, so dropped it to 3), and set riser height to twice the original (ex: from 6 3/4" to 13 1/2").
This is because the first tread of the right side can't be half-height. Draw it in as a Landing (you'll have to set it's height and thickness manually)
 I suppose you could keep it 4 treads and sink it into the floor but that's rather inelegant.
Oh, and on the right stair, be sure to check Riser Surface at Top Landing on the style panel.

Oh they're up on the Attic Floor.

Check the Wall Cap panel

In my experience the program is never (rarely?) wrong in these calculations, it's just sometimes unclear what is being calculated, or how.
I have no idea if X1 had this but I assume it did, but a Living Area polyline will show you exactly what's being calculated.
 
They have an article on this: https://www.chiefarchitect.com/support/article/KB-00424/understanding-how-the-square-footage-or-living-area-is-calculated.html

Indeed, there is no "wall height". Ceilings heights set the height of the walls around a given room.
Check out their video on story-and-a-half roofs: https://www.chiefarchitect.com/videos/watch/1605/designing-a-one-and-a-half-story-roof.html

Not if it's in the Library Browser, that's the whole point of saving Line Styles and Walls and Moldings, etc etc, is that they don't need to exist in the plan. you just Select that Library object and then click and drag on the plan to create that object. Once you do that, that Wall Type exists as part of that plan.
 
I just tested it, made a Siding-6 with two layers of siding, add to Library, open New Plan, grabbed it in my library and drew out a wall using that new definition.
There's no Import process, you just use it.

Would need to know more about these rooms to say for sure.  Also might help to know what version of the software you're using.
Fairly certain though that it just automatically places the right type of outlets for type of room you're placing them in. For example, Deck rooms are treated like outside rooms and get outside outlets, and if your rooms are not properly defined at all (like, you can't select the room) then their walls are treated as exterior walls.
 
Post the plan here if you're not able to sort it out.

This is the way.
 
The issue you'll likely start screaming about though is the "auto merge collinear walls" setting that kicks on the second you look at your railings wrong. It's in General Wall Defaults. I generally leave it on but sometimes there's a plan that I really need it to stop "helping".

It looks like those walls are set to be solid railing walls? That will happen when doors are placed in railings. If that's the case, try unchecking Railing on those walls, let the room's Ceiling height set the wall heights.

When you hit Build New Floor, take a look at the options, there's one for floor heights and one for roofs.

So you drew the existing walls, set them to a "Walls, Existing" layer, then hid it? Those walls are still there. You don't want hidden walls, they're still there and affecting the model. You'll be better off drawing them with CAD or using some form of mask. Check out their resources https://www.chiefarchitect.com/search/?default_tab=all&q=as+built

Can't see how a new computer would affect that, but check the dimension defaults, Locate Manual and Locate End to End, specifically. If they're not set to locate things, they won't. I'd wonder what Dimension Default you're using, too, since they'll behave different depending on view. It'd be pretty surprising if you experienced this same thing in all views.

Okay. We're mixing up using Transform/Replicate and just manually rotating. Also I'm not sure how "About Current Point" only lights up with a Point Marker, that doesn't make sense to me.
 
Place a "CAD Point" (not Marker) at the hinge, then in the Edit menu change your Edit Behavior to "Rotate About Current Point". That specifically affects your manual actions using object handles etc.  Transform/Replicate also uses CAD Points, but that's where the "About Current Point" option comes in. Not sure why thats not working for you.
 
Frankly I don't use Transform's Reflect often, I'd just use the normal Reflect About tool for that.

Labels are controlled by the Layer the thing is on.
With ALDO open, select a Roof Plane, you'll see the Roof Labels layer, select it, you'll see at the bottom what Text Style its using and can Define from there.

Easier solution. resize this one smaller

 

 
then back again

 

Yeah definitely want to ask the HomeTalk forums. It appears HD does have the same blend function https://www.homedesignersoftware.com/support/article/KB-00131/using-the-blend-colors-with-materials-tool.html but I don't know if it had it in 2016.
 
I suspect you should still be able to use the Adjust Material tool though. On the Texture panel there should be an option to blend the color there. The color chooser allows you to eyedropper a color from anywhere on your screen, so if you open your library browser to that material beforehand you should be able to pick it up from there.
 

Overhang's too short. Pull em like an inch out from the wall and they'll be fine.

How?
 
If you used the "Hole in Floor" tool, then it won't Don't use that. Make an "Open Below" room and it'll show stairs below.
https://www.chiefarchitect.com/support/article/KB-00757/creating-a-stairwell.html

Frustratingly, no.
When you use the Object Eyedropper, hit the Select Properties to Paint button in the lower left to see all the things that can be picked up and applied onto other objects. Railing walls have the "is railing" setting but none of the newel or baluster settings that would be needed.

Both Foundation Dimension Defaults and Post Layout Dimension Defaults are set to use the same Dimensions, Plan layer.
You'll want to create separate layers for each to really separate them.
 
Same with your Text defaults, they're both using the generic "Text" layer.

Yeah. I totally get that.
 
Interesting issue I can't say I've encountered before.
I pulled your Beams away and the original Framing dimension followed it like I'd expect, but when drawing new angular dimensions I see two things happening:
1) I can still draw a dimension to the "center" of where the beam WAS - which appears to be the railing above, even though it's not displayed AND the dimension defaults are set not to even locate walls.
and
2) as long as they're away from those hidden railings, a new angular dimension does attach to the sides as expected.

Kind of a pain but you can pull those beams out, dimension them, them center-align them back into position.
 
Also, are you aware that those railings on Floor 1 that these dimensions are snapping to are uh, for lack of a better term, subterranean?

MacOS doesn't work the way Windows does, programs don't install into a folder structure that you browse around. Instead they're just self-contained programs.
If you go to your Applications list and find Chief Architect, you should be able to Right-click or Option-click there's an option to access its contents.
Once in there, it'll be similar, you should see a resources\buttons folder.

That gap is common in exterior type rooms. Its the roof ceiling surface being placed under the full rafter depth, you don't normally see that because there's usually a wall there covering it up. If those roof plane's stud thickness can be reduced then that'll take care of it. But a quick fix is actually in the porch room specification. Under the Roof section there's an option to Use Soffit Surface for Ceiling. This reduces the rafters over the entire room, instead of just at the eaves.

Should just need to break and curve the section of wall where the flare begins.

Probably helps to turn off Snaps, they'll probably just get in the way. Lots of eye-balling to match the walls curve to the flare.