Hi!
I hate to be the bearer of bad news, but generally 2 bettas of any type - regardless of sex - can not be put together. If it's 2 males, they'll fight and end up severely injuring or killing each other. Same story, I guess, with a male/female combo. And with 2 females, generally there is one dominant one and one that gets harrassed constantly.
As far as putting bettas in with other things - some people will say they are okay community fish, but I, personally, would never put a male betta in with anything except maybe an african dwarf frog and/or some white clouds. Their temperment is just too risky to "test out", unless you have a backup plan in the event you'd have to pull him from the tank.
If you're going to have guppies in the tank, bettas are also a really bad idea because they're very nippy and will probably end up killing them.
More bad news - you won't be able to add the goldfish in with the other fish you're thinking of because the goldfish is very much a cold water fish, while the others are tropicals. There is at least a 10 degree difference in the water temp that each likes to have. Also the goldfish will produce too much waste to be in with other fish in a tank that size.
Have you cycled your tank? How long has it been set up?