get more than just 2 more otos, they like to be in groups. don't get any more angels, as they can get rather mean towards each other as they grow up. get the 5 neons, to up the school, since they like larger groups too.
as for having 'enough water'..... do you have lots of decor, plants, hiding spots in your tank? what are you running for filtration? what is your water change schedule? those are all variables.
your guppies, are they all male or mixed gender? if mixed, don't bother buying more, since you'll have more than you can fathom in a short while, lol!
keep an eye on your 3 current angels for aggression as they get bigger and be ready to separate them if need be. i had two in the same tank for a while as they grew and as soon as they hit maturity they tried killing each other.