I currently have a 10 gal nano that has been going for just about 4 yrs now. I have to say that I love it. I did for a short time upgrade to a 25 gal but dropped back to my 10 gal.
100 watt heater like mentioned is to hot, a 50 watt is what I run and that is all you would need for this size of tank.
I am running the small AquaClear 20 on my tank. But I am going to try my 50 on this tank instead. I don't know about using 2 of them. You might find things blowing all over, maybe someone who uses two of these in a 10 gal can give their opinion. But just the one 20 alone is not enough IMO
As for fish, I do love the damsel family but do yourself a huge favor and don't put them into this tank. You will only have headaches believe me. It is just to small for these types of fish.
I would recommend 2 fish max. The false percs, blennies, gobies, firefish like mentioned earlier are all good for this size of tank.
Don't over load your cleanup crew in this size of tank. I have one very large turbo snail and one small cowrie which I have had forever. I would not add anymore snails than that to this size of tank. Don't go overboard if you do crabs either. There is just not enough "natural" food source for alot of crabs as I found out the hard way too.
I do have 1 coral banded shrimp. You need a shrimp, they are so much fun to watch. If I had to do a shrimp again I would do a Skunk Cleaner Shrimp...
I have assorted mushrooms, toadstool leather, bubble tip anemone. Now for the anemone if I had to do it again I would probably skip it. I do love them and so does my clownfish but since mine has split into 2 of them it just does not look the same. I do spot feed mine once a week and run pc lights. But I think it would do alot better in a bigger tank and of course different lights.
The 20 watt 50/50 you are talking about are nice lights for the easy corals like mushrooms, leathers etc. If you want to get into the higher light corals then the 20", 96watt 50/50 Power Compact strip light is what you want to get. Many on this site have this light so you can ask them how they like it etc.
I see you mentioned about moving to the 29 gal. If that is your longterm goal I would go for that size right off the bat so you can setup a system and get it going without having to upgrade later on.
Another learning lesson I have done over my 4 years in this hobby. Leave all urchins and starfish for the bigger reef aquariums.....
Had them both and they did not live that long in a 10 gal.
I hope this helps you out a bit, these are things that I have done and been through with my tank. I still love my 10 gal and would not give it up.
Good luck and do post some pictures for us as you go along...