They probably reused a lot of ideas in Turbo Pascal 4.0. It had units which were very similar to Modula 2 modules, except that interface and implementation were in a single file.
Most of those ideas come from USCD Pascal, and the later Object Pascal introduced in Turbo Pascal 5.5 came from Apple's Object Pascal, which was derived from Clascal and developed in collaboration with Wirth.
Probably, but there were many other language differences in Modula-2 that made it a better language. I suspect the real reason was the usual one: inertia. A lot more people knew Pascal and thus more bought TP than TM2. <something something about technical merit and popularity contests>