It is entirely dependent on the betta's personality as to whether he gets on with the other fish or not. Working on your average, relatively-docile-but-not-tolerant-of-everything betta, I would not recommend guppies. Sometimes it works, but you are right - sometimes the tails are just asking for trouble. Personally, I wouldn't risk it.
How big do the Golden Nuggets get? I would choose between either the pleco OR the cories, not both. Lemon tetras are also nice, but those + the glowlights would be your maximum. You have room for a betta + two schools (either tetras or bottom feeders or both), or a betta + a school (be it cories of tetras) + a pleco. Anything else would really be pushing it.
That said, have you considered Endlers? They are a safer bet than guppies.