Gymnastics isn't fair or equal. It never has been, and it never will be. Some kids have more natural strength, some kids have more natural flexibility, some kids have better intuition for the mechanics of skills, some kids are more comfortable in the air, some kids have access to better facilities, some kids have access to better coaches, some kids can afford more private lessons, etc, etc, etc.
Differences in lighting and camera angle in a virtual meet are but one more thing to add to the long list of things about gymnastics that are unfair. But unless you're competing for a scholarship or a spot on the national team, differences of plus or minus a few tenths are ultimately inconsequential. And during a global pandemic, I can think of a million things that rank higher on the priority list than "avoiding negligible and inconsequential scoring biases in amateur youth sports."
As long as we're keeping kids healthy and active, they're getting what they need to be getting out of the sport. I don't see any reason to worry about whether camera angles might have bumped some kid's score up or down by a tenth or two.
As for allowing retakes, honestly I think it might even make things more fair, by removing a little bit of luck from the equation. Sometimes you have a random fall where you wouldn't normally, and this happens to even the best gymnasts. By allowing a retake, you're removing the element of luck from the equation, and allowing the gymnast to show the best she's capable of. Isn't that what we ultimately want at meets? For each athlete to show the best they are capable of?
(That said, I would prefer for there to be a policy applied across the board: say, each gymnast can have at most two retakes, and state that up front)