Sanders getting the nomination would require him to twist the few "left-wing" positions he holds rightward in order to secure the Democrats' Wall Street funding base, yes. I don't think that's really disputable. Of course, as a reliable funder of American imperialism, he probably wouldn't have a tough time securing funds from defense contractors, which could make up the difference.
Well he'd presumably win the primary in this scenario despite the best efforts of the Democratic-leaning Wall Street donors. In which case, he could just spurn them upon receiving the nomination. It would depend on how much principle he has.