Never had a problem with my sixline.....quite the peaceful fish....loved the activity it provided however, always busy around the rock work...
I hear Royal Gramma's can be a terror though.
I am looking at putting a pair of clowns in my 29...and that is about it...nothing else in the way of fish...will be some inverts and corals, but those will probably be the only two fish.
For your stocklist:
Clowns
Shrimp gobies
Randall's Goby
Firefish (personally I like the purple one, but they are a little more expensive)
Clown Goby
Neon Goby
Jawfish (entertaining to watch...unfortunately they are jumpers, make sure you have a lid or some other cover, eggcrate, etc....I lost mine cause it jumped and I had no cover)
Lawnmower Blenny
Longnose Hawkfish (pretty cool)...don't have a swim bladder, so they tend to just swim long enough to find somewhere to perch
Plenty of small guys to choose from...just do some research and make sure they are compatible....
Personally, other than green chromis (because it is cool to see a school of them), I stay away from Damsels. Royal Gramma's are cool, I have never had any experiece with them, but have seen them returned several times at a LFS because they were rather nasty...Good luck...