Nope, they are definately NOT compatible. If you want more of a community tank, I would go with the Guppies and choose some fish to go with them. Bettas can't be kept with many other fish. What size is your tank?
Bettas cannot be kept with any fish with fancy fins and they are not compatiible with gouramis because they are related to them. (definitely NOT kissing cousins) They don't like to be kept with their own kind. If you want a male, one betta to a tank please. If you want females, try to have at least 3 so there can be a primary and here "court". Do not mix them in the same tank because sooner or later chances are one or the other of the sexes will be wanting to spawn and it will be pure chaos. Breeding bettas is NOT like breeding guppies or other livebearers. For that fact, breeding bettas is not like breeding any other fish due to the amount of space and time involved in maintenance after the fry are partially grown. (not a job for the weak or underdedicated)
Now, please don't let me talk you out of a betta. I am just saying like I have heard Gunnie say in her posts. Consider making A betta the focal point of your tank and perhaps put some Cories in with him or some Otos and you will be surprised at what a lovely tank you will have. But I would put the Cories or Otos or other fish in firsh so they can establish their territories first so you don't have a bossy betta.
The compatibility chart that I use recommends as possible fish with bettas: dwarf gouramis (but no one I know with actual experience recommends that)
platties (this is possible, they're fairly peaceful fish but I've never tried it)
corydoras catfish (I can attest that this can work after a period of initial hostility on the betta's part)
otos (chickadee can attest better than me but she's had hers for a while and it works out) danios (they have a fin nipping rep but supposedly this is mostly among themselves and similar minnow like fish.)
the more gentle tetra species (again, this is like with the danios, and you want to be careful) cherry barbs and golden barbs (I've kept those before and they seemed pretty gentle. You don't see many golden barbs around now anyway)
The thing is, a lot of the schooling fish need a school to be happy, the platys need ideally two females and a male to be happy, and the betta needs his space to be happy. As chickadee often says, they aren't used to sharing space and they'll need to be able to have enough room to stake out a territory. I think part of why my arrangement works is that the corys and the betta tend to live in different parts of the tank and I also have a fair amount of plants and rocks so that all of them can hide if they want to.
You are probably right about the space and hiding places being the key. The more space a betta has the more docile it is.
The only bone I have to pick with your compatibility chart is that I would never under any circumstances put a betta in with any kind of gourami (even the dwarf kind). They are related and I am just afraid you would take a very big chance at losing one or the other beautiful fish as the betta would not accept it most likely. I am also not too sure about the barbs as they are rated semi-aggressive, but I have never seen anyone try it or maybe have forgotten it if I have.
I doubt it too, Rose, since I've seen in my cousin's tank how the gouramis she has pick on each other. Hard to say, I don't think I'd want to try it.
As for rosey and golden barbs, I'm not sure how they'd be with a betta but I talked to someone who has a community tank and she said they are really peaceful little fish. They need to be kept in pairs.
The only fish I would personally try keeping with the males are Cories or Otos. With the females, danios or peaceful tetras should work. I would never risk keeping Bettas with any livebearers or barbs, and certainly not Gouramis.
I think platys would be okay, like Omorrokh says, but guppies are definitely out. Catfish seem to do just fine after the initial breaking in period. Like I have said in other posts though, the word with adding fish to a betta tank as with other aspects of betta behavior is PATIENCE. They have had the most unusual upbringing of all fish I know of by being seperated from all other fish so be patient with them and they WILL get the idea soon enough.