right, dwarf gourami's, your best with either just 1 male or 1 male and 2 females. don't keep them 1:1. you've mentioned you like the colours of them, have you seen any pics of the females, they are a lot less vibrant and colourful, so you may decide to just keep the 1 male if you see them. up to you anyway but this will make quite a big difference on how many other fish you can get.
Personally I do like DG's and I've never had any problems keeping them, however they can be somewhat weak, there's a great pinned topic on them
here so have a read of that before you take the plunge! also I think it'd be best to get the other fish first and make sure the tank is a few months old and running with no problems before you add them.
the smaller species, get groups of at least 6, a few more if you can but don't overcrowd them. it depends a little on how many DG's you decide you want.
if it was me I'd get this combination
1m DG - 2"
8 Cardinals - 8"
8 microrasbora galaxy - 4"
this gives you 14" of fish, the maximum for your tank is 16 so your a little under but it's a very comfortable stocking level.
the heavier you stock the less margin for error you have with water quality so for your first tank I'd highly recommend you keep the stocking light.