the minimum wage thing you speak of is on the businesses that employ people not on immigrants themselves. Businesses will absolutely do the legal bare minimum for their employees which is why certain things that should absolutely be a no brainer end up needing to be legislated. Things like max working hours and breaks and safety issues. Things like equal opportunity hiring and creative dismissal. Things like minimum age allowed to work.

None of that is an immigration issue. If businesses can get away with employing foreign workers less because they'll accept it (because lets face it, if you can't speak English in an English country and you have to support a newly arrived family quickly then any job coming at you you gotta grab!). In most countries (i know it to be true of mine) you must look to hire from people within the country first before looking at candidates from other countries. It doesn't apply to people already migrated into the area. So naturally you need to force a higher minimum wage.

And i don't think you mean Native Americans in the context here. Naturalised Americans perhaps or American Citizens.

I can't speak as to the racism you are talking about because I live in a radically different culture from the US. I won't make comment on your political parts.