B: ん？ あぁ、この辺はドシロウトにできるこっちゃないからな。 邪魔にならねぇように先にメシでも食って、後は舞台袖ででも大人しくしてな
Pretty much in general でも and ても don't sit well in my mind. There have been a lot of times I see them in a context in which they don't make sense to me as "even" or "even if/though" or in the case of でも as で and も individually. In this case the manner of speech is colloquial so maybe that's why it seems so odd. What really confuses me is ででも. Can someone explain the use でも and ででも here?
As a bonus, is にならねぇ just にならない with a a different emphasis?