Hello! from your descriptions, you seem to say that your work and home setup produce different results - namely that at home, your sketch is not shown in the section view (screenshot) while at work it is shown. So I investigated some things in my setup (Creo 3.0 M130)
So for your second Q, this drawing option seems promising:
remove_cosms_from_xsecs
(in drawing mode, file->prepare->drawing properties->detail options (change)->find->(search descriptions)->type keyword "cosm"->find now)
If set to "trim", then system removes from display the portion of datum curves and cosmetic features that is in front of section cutting plane.
If set to "total" (default), then only things entirely in front of the cutting plane will be removed from view...
Now the long winded answer to your first Q:
So cosmetic sketches are a bit of an oddball and perhaps it is wise to avoid them. They are very handy when you are dealing with non-parametric things such as logos and labels that contain a lot of entities because you can use the "under-constrained" mode and essentially doodle something without the system crawling to a stop trying to solve all the sketcher constraints!
And another thing I learned during this investigation, is that cosmetic sketches they are drawn on a plane that is orthogonal to the view plane will not be shown in that view. This answers why your cosmetic sketches are not showing up on any orthogonal projection views.
You can tilt the sketch plane about 0.1degrees and get a decent looking result. But why use such a hack when a regular sketch can suffice?
One more thing about cosmetic sketches - you can right-click on a view and "erase/show cosmetics". So that's one way to control the visibility of cosmetic sketches and so that can be an answer to your first Q. Unfortunately, that is not a great solution if you have threaded holes and you do want the cosmetic threads to stay shown in the view!
So the "proper" method already mentioned in this thread is to put your sketches or cosmetic sketches on layers that can be blanked or shown on a per-view basis.
Layers are not easily explained, so if you don't know what I'm saying, you need to invest some time learning by reading these forums (just search for "layer" and go through the found discussions) and other online help (just google "creo layers")