Groovy Baby! Love it! I think if you are going to have a strong look like this, you have to go the whole hog to pull it off, otherwise it just looks like a bad take on a 'theme'; you nailed it, very well done!

How about some photos? What style? A mid-tone grey would look good with black sofas:

Well, you don’t want your trim to be glossy. You want semi-gloss and yes, they can, and yes, there are multiple finishes in every paint line. Have a chat with your painter. Go with Benjamin Moore White Dove in SEMI-GLOSS,

Your home looks cozy. Cant really tell what is the existing colour on the walls? Is it white? Try painting a sample of sage green. Look at a tone that you like. If all else fails, speak to a creative designer who could come to your home and help you re-look your space.