Okay, Destroy Shep first...
As far as I'm concerned, it's her mom's search and rescue that finds Yoshimi Shepard on the wreckage of the Citadel, along with a few surviving reaper prisoners. Yoshimi's rushed onto the ship, where she's given emergency medical treatment. Her amp and omnitool are both malfunctioning, and eventually have to be removed. Her muscle control never recovers entirely, and the heavily augmented Shepard spends the rest of her life with tremors. Her mind's still intact, though, and she's reunited in short order with Kaidan. Since she's no longer physically capable of being a Spectre, Yoshimi retires to help the recovery effort. And adopts kids, gets married to her Spectre boyfriend, and has a pretty happy life. She stays in touch with her old friends, and if she has any regrets, she never voices them.
And in the case of my control-Shep, EVERYONE GETS MARRIED. Kaidan and Liara got married. Joker and EDI get robot married. Ken and Gabby get married. Heck, maybe even Jack and James get married (THIS IS MY HEADFLUFF DON'T JUDGE). Eventually, even Garrus stops sulking over Shepard's death, and later, gets married to Tali.
And none of them (except EDI) ever know about the AI in the Citadel that's watching it all happen with a vague monolithic sense of approval.