Number 3 is really hard.

It's not Irving Berlin nor is it Doris Day. And $20 million dollars is a lot of money even today. So it's probably one of the super-rich.

Doris Day appeared in films with Cary Grant who was briefly married to Barbara Hutton who was super-rich. But she famously squandered her own inheritance and didn't get it back. So that line of enquiry seems to be a cul-de-sac. Arrgh.

Okay - is it Geraldine Rockefeller?

Nope - I'll give you Doris Day. Day's third husband Melcher did the dirt on her, forcing her into relaunching her career on TV after his death to finnace the debts she suddenly found she had as well as keep her son fed. That's her in the pic and her singing too in the clue.

Her case against his accomplice was settled in her favour for that amount, but not until the mid 70s so there may have been some adjustment for inflation etc.