I'm laughing while I read your post, and wondering if you're writing about MY son! Ha! Okay, so now you know that I totally don't think it's actually funny. It's very frustrating from a parent's perspective. My son is 22 months so not quite 2, but he's very rigid in his routine. The slightest deviation, as Hannah G says, causes a total meltdown.
We warn, warn, warn. 10 minutes until X happens, 5 minutes, 3,2,1 minute, then 30 seconds, then 15 seconds, then we count down from 10 seconds. We have to be consistent - if you say "time's up" you have to mean it, no matter what. And if he tantrums anyway, we say "I warned you we were getting out of the bath, remember? We counted backwards from 10 and now it's time to get dressed!" This tactic has actually been tremendous for us. Our son is very responsive to warnings and we rarely ever get a meltdown if we plan ahead this way.
Food. It's time for mom to stop caring about food. He gets up in the morning and is freaking out first thing, which says to me that eating has become an issue. Totally give up. Provide the choices, don't mention a word if he eats or doesn't eat. No big deal. When we stopped caring, our son transformed into a child that loves to eat. My son IS skinny, he's gained 2 pounds since he was 9 months old. I read all about food hang-ups in "what to expect the toddler years" and I tried all the tactics and they work! But the most important one in our house is to not make an issue of eating - don't praise when he does eat, don't scold when he doesn't, and don't make him taste something he doesn't want to taste. My son is not picky anymore. He won't try everything, but his diet's variety has improved drastically since I stopped making a big deal of it. I also don't worry so much about feeding him a large variety. He might eat the same thing for dinner 3 or 4 nights in a row, and that's comforting to him. And toddlers love to dip stuff and graze - offer lots of snacks, just leave them out for him to try! Turns out my son LOVES olives! Green and black.
My favorite phrase with my son is "pick your battles". If he is upset about clothes I've put on him, then I change him. I usually give him 2 new choices and let him pick one. Sometimes I let him just pull what he wants out of his drawers. Our hang-ups about outfits and matching are just that: our own. If my son won't wear a jacket and it's 40 degrees out, well, I put the jacket in the car and when he's shivering, I ask if he wants his jacket on. Almost always he's learned by this point, that it's cold and his jacket will be warm.
I would totally get the white mat. Why make the kid crazy? It's not going to teach him a lesson to make him bathe with the beige mat, is it? 2 year olds can't be reasoned with. If he was 3, I might suggest sticking to the beige mat...
My son also picks up crumbs and puts them in the garbage. Sometimes I can't even see the crumbs. But it's great, because my 8 month old is learning to crawl and he's helping to keep the floor clear of hazards!! All this behavior is totally normal. Good luck!!