oooo... ok - leme start:
First, your stones will bury and unbury themselves and make it very difficult for your plants to root... I've actually tried this out of laziness once and it's... not as cool as it seems.
Second, I recommend that instead of 2-4 angelfish, you get either 1 or 6+. Why? they'll beat each other up and just get all scarred up and ugly if you keep 2-4.
Third, If you do CO2 with the dry method, the CO2 will just go into the air and... well, unless you put a plastic bag over the tank or something to trap it in...
Otherwise it's a great sounding idea... so here's what I would change:
Get rid of the stones in the substrate - use large stones as decor instead. Just use a small 1mm grain size sand or something. Do the dry method for HC, I hear it works great, but save the CO2 for when the tank is filled with water. If you must get rams, just get rams. If you want Angels, just get angels. Rams are more colorful, though, and Angels are prone to beating the crap out of each other. (I keep mostly angels, so don't think I"m trying to get you to not keep them)
Aalllrighty - those are my suggestions.