Rotkeils work nice with them ime, I've also had them with a group of wild Peru scalare. I've done both combos in a 75 (or larger), plus some tetras, L200 and L260 pleco (you can sub similar small to medium plecs or cats).
The problem I see with sevs, angels, etc. in your tank as it is, or with adding too many fish, is with the deep gravel you have, you've reduced the height of the tank, making it short for tall bodied fish. Also (if you have some tank height) guianacara tend toward the mid and lower part of the tank, sevs and angels mid and upper, part of why they work so well with eartheater types. Also, between that and all the rocks and other décor, you've effectively reduced your tank size a good bit. For what you'd like to do I'd both reduce the gravel down a few inches and open up the aquascape, meaning take out most of the solid, water displacing stuff and replace it with some plants, a few branches, less and/or smaller rock, etc.