Oh yes, this marriage has been an absolute nightmare for the Royal Family. If it isn't Harry and Meghan in the middle of some controversy or scandal, it's the psycho Markles.
I don't know how much vetting went on, but there should have been more. It's hindsight now, but Harry was in such hurry to marry Meghan and the Queen pretty much went along with it, but it's been written that she had reservations. Harry should have been told to hold his horses while BP checked into Meghan and her family, especially when she gave the Royals the sob story about being estranged from her awful family and the lies she told about her father back then. That would have been enough to say, "Whoa, we need to check all this out thoroughly." If Harry got his pants in a wad, so what? At that time, he was giving HM ultimatums and really, bullying her into letting the marriage go ahead.
I was thinking, this could backfire on Meghan. All her statements about she knew for a long time this secret about her father and didn't tell, if she and Harry were to part, the Royal Family could come back and tell her, she that she knew her father was taking part in criminal activity (of the worst kind) and withheld the info from them, so she was, aiding and abetting her father through her knowledge all the years of marriage. It's a stretch, but I would do it, especially for Markle.
This is assuming that the story about Tom Sr. is the truth and proven.