Looks like everyone else has you covered pretty well. :)
I just wanted to put in my 2 cents though about adding him to that community.
If he is timid, putting him in any community tank might be even more of a stressful situation, so I do not recommend it. And even more; he would inhabit the same layers of space as the gourami, as they are both labrynth fish. And gouramis..well I can tell you from personal experience that some of them can be aggressive to others; and given they would inhabit the same space I feel it would be a recipe for disaster.
If you think he might be bored (which is quite possible), you could keep him next to the other betta tank so he has someone to occupy his time when you aren't around to entertain him. If he is rather "delicate" you might want to consider putting a card between them though, so you can control how much of each other they see.