Chopsaw

Yes of course,   check one of the longer measurements that are dimensioned and calculate the ratio then select everything and use transform and replicate to make the adjustment.  Or you may have not used the correct import settings. This can also be checked by measuring and calculating the existing ratio.

Yes you can curve a ceiling plane or a roof plane that can include a ceiling.
 
Curved Ceiling: Check Curved Ceiling to specify the selected ceiling plane as curved. See Curved Roof Planes. Specify the ceiling plane’s Angle at Eave, Angle at Ridge and Radius to Framing Bottom. These three values are interrelated - when one is changed, the other two adjust accordingly. You may find it helpful to first specify the Radius value, then the Angle values. A flat ceiling plane with a pitch of 0 has angles of 0 at both the ridge and eave, as well as a radius of 0.

I am not sure you can auto dimension exterior walls to the center of framing but you can certainly move you dimension snaps to that location if you set it to.
 

It seems maybe there is still a quirk with that and this has to be the oddest work around ever imaginable.  Try running "plan check" and see if that resolves the issue. 

There are some cad blocked examples in your Core Catalog but personally I prefer to do a schedule that is limited to what is included in your specific plan rather than throw out every thing under the sun.
 

 
 

Snap a couple of cad lines to your roof plane and the angle dimension tool should be happy to attach to those in elevation view.
 
 
 

Quite likely that is the issue if you overlooked that step.
 
Tools > Layout > Referenced Plan Files...

I think your best option would be to draw that as a door with a raised sill.
 

Yes you can select and delete but your original question was to turn off the layer as it may be useful again later on.
If you dock the " Active Layer Display Options " it should tell you what layer the PDF is on when selected.
X14 uses the " CAD, Default "  layer for imported PDF's.
 
Note that Eric posted an X15 screen shot above.
 
Be aware that there may be plenty of other things on the CAD, Default layer so that is why they changed it for X15.

3D solid is not possible in a Cad Detail View.  Sorry.   Paste back and forth perhaps ?

That is just a reminder that you have "Auto Rebuild Terrain" turned off and have made a terrain modification that is not displayed.  Your terrain needs to be rebuilt.   No reason to have that turned off unless you are having significant computer performance issues.
 

You are likely overthinking this one.  Decide what size the step is going to be and place a dash ahead of it for your floor level of the deck so it is a negative value.  Done.
 

It sounds like maybe you are trying to use the 2D people.  They are primarily meant to be used in elevation views.
 
Try these or do a search on the forum for 3D People.
 
https://www.chiefarchitect.com/3d-library/index.php?r=site/detail/1222
 
 

It looks to me that what you are building would most suitably be a symbol so just do the math....
 

 
 

It looks to me as you may have colour toggle off in your section view.  

The Specification Dialogues are a little different now but it all works the same way.
 

 
Gives you this:    Which is actually the default setup in x14.
 

 
 
 
 

Yes,  Always print to PDF to review before printing.  PDF viewers should give you a magnification level setting...  ie 100%
 
Then print from the PDF for most predictable results.

That is definitely a bit odd but x14 is the same.  Fortunately it only appears that way on the child toolbar.  So you get rid of the problem when you graduate.  But all the same quite confusing for new users.   Might be a good idea to submit it and find out what the issue is.

Try changing the scale of your drawing sheet in plan.

You can usually just place a double break and then tear a strip completely out for a quick method on a simple plane.
 
See video demo posted below.

It looks like you may have the opposite problem as discussed here:
 
Same solution though I think.
 
 

I have not noticed any significant changes in the viewer for quite a while now.  At least in comparison to the number of suggestions.
 
Your status bar will display the number of surfaces rendered in a 3D view for a short time after it finishes rendering if that helps.

Sorry I don't have a Mac but it should be the same I would think ?
 

Soffits can work depending on the situation.