No worries about the zone (I just did a hyphen after state and added it there).
If you can get more light on the leaves of the meyer lemon that
should help it recover.
One of the issues I've always had with moving trees or potted plants indoors is bug eggs hatching out.
I have had friends overwater but that usually shows up as browning along the leaf edges and your tree isn't showing that.
It actually looks like it is overwintering well, except for the bug sign.
When you bring it out in spring don't forget that it will need to be "hardened off" (a few hours per day outdoors until it adjusts to the normal surrounding weather will keep shock from getting it).
I plan on planting some citrus trees but I'll be putting up winter houses over them (I'm in zone 8a and if I put up a temp. double glazed conservatory, they will survive our brief winters).
If you were to decide to give that method a try, you can add a heat source to keep the temperature up
enough. I've used smudge pots in the past but I may end up building a true conservatory with a
rocket mass heater.
The leaf damage I can see could be; leaf miners or white flies.