Advice on training a cat... please?! We desperately need help.?

I'm going to try writing this question again and phrase it with a bit more kindness. My mother moved in with us in May with her little tiny kitten. Said kitten is now about a year old, give or take a few months, and she is a terror. Admittedly, I don't like cats, but I have dealt with them in the past. I have lived with the scratching furniture and rugs until we successfully taught them only to scratch their post, and I have dealt with teaching them that they do not belong on furniture and tables. My mother, my husband, and myself have all tried tirelessly to teach this animal to behave. She has toys, a tree house type thing, and a kitty condo so being bored is not her problem. I understand that kittens are hyper by nature, that's fine, but even my mother (who has owned plenty of cats in her life) says that she is by far the worst she has ever seen. I know that this cat has potential to be wonderful, because at night when everybody is sitting on the couch she will sleepily walk up and snuggle under my husband's chin or on one of my shoulders or even on one of my three year old twins' laps. I know she can be sweet, and in moments like that I actually might love her. But then there are moments like this morning, when I woke up to a destroyed living room. My husband and children begged me to let them put up a Christmas tree now, so eventually I agreed. Now I wake up every morning to ornaments, garland, and lights all over the place. I even went so far as to place everything higher up so nothing was hanging off the tree at her level, but she still grabs everything. We've tried spray vinegar on and around the tree (at suggestion of my friend) but it did nothing. I am sick of looking at chewed blinds, a destroyed Christmas tree, and cat hair on my kitchen counters. How do I train this animal? I need to stop stressing over her and she needs to learn her boundaries. I really do not want to have to ask my mom to get rid of this animal, but I'm reaching my limit. By the way, if it matters, I never yell at or anything like that. Believe me, I am extremely tempted to scream, but somehow I refrain because I know that does nothing to help.