I have completed the game, with all 242 stars. In final two stars, the first took 10:42.25 and 5 lives, and the second took 11:36.90 and 7 lives. For these two, I did not get any Game Overs, nor did I go back to Starship Mario to replenish lives.
I did not think the game was as challenging as everyone says, to be honest. Yes, it is more difficult than SMG, but I found only a handful of stars to be particularly frustrating.