I have only frozen one kind of squash raw, a triamble squash. It was terrible, weird texture when thawed, just not good (the part that was cooked before freezing was excellent). Since then, I cook squash first, I get much better outcomes. I have never frozen spaghetti squash in any form though, so I can't say results would be the same.

It'll keep fresh for months. I'd keep it in a dry place though, not humid.

I always freeze my spaghetti squash, in zip lock baggies. I just thaw it out and stick in whatever I want ...it cooks very quickly...not quite sure what you're asking ...but it's basically a vegetable...you can add it to water based things(soups, stew), or sautee it...It will only get mushy if you overcook it. I have a large pot and can fit 4 in it at once..I put a couple inches of water in the pot, poke a hole in each squash, then steam till the sides are mushy. Then I let them cool, so I can handle them, deseed them, and bag them up...so mine are partially cooked before I freeze, and it's not mushy...mushy is from overcooking.

I store mine in a hallway closet, cool, dark, and dry. I am not sure about that advice for humidity...kind of goes against my instincts for squash...you want humidity for carrots..but not hard rinded squash...I have found that it takes just as much time to steam 1 as four, so I usually just get them done and in the freezer. Spaghetti squash will last 4 or 5 months...but they are just not one of those squashes that will keep a year.