If you're going to use epoxy again on a bridge reglue, don't mask it. There is no need. Remove all the tape and then apply the epoxy and clamp the bridge in place.
Use Q-tips to wipe off any squeezeout around the bridge after you put your clamps on, and if there are any stubborn spots, dampen the Q-tip with mineral spirits. It will take it right off. But you want to be sure it's taken enough of a set that the mineral spirits won't creep under the bridge and affect the integrity of the joint.
Also FWIW, if using epoxy, use CA glue to harden the top first, especially if you're working on a plywood top. The CA glue will secure the plies together and make for a much stronger final joint. Basically the CA unifies the plies and turns them into a cohesive surface for the epoxy to bond to. If you don't do this, the plies are likely to come up again in time, as epoxy is very thick and will not penetrate to the deeper plies like CA glue will.
As for dealing with the guitar in the picture, all solutions are extremely time consuming and likely to have lackluster results, even with extreme care. A Kovax sanding block with a small strip of sandpaper, wet sanding with water and Wool Lube / Detergent, can get the epoxy off eventually, but you'll have to buff out the surrounding area after, and also be extremely careful to avoid going through the clear and especially the color coat. And the finish on that top does not look very thick.
The most likely scenario is you'll make some progress with that and it'll look good, then a couple swipes of wet sanding too far, and you'll see a nice patch the color of bare wood, which will look horrible against the black.
If you're comfortable using an airbrush, you could mix up some black pigment *and* black dye, and do a partial refinish. Black is, in my opinion, the easiest color to touch up, and the easiest color to mix (aside from pure stark white), so if you wet sanded down around the bridge, even if you went to bare wood, doing a refinish with black nitro would not be that difficult, except for one thing --
The bridge of complicates that greatly, and even with careful masking, you're going to get black lacquer onto the edge of the bridge closest to the top, and attempting to remove that even very carefully with a Q-tip dampened with lacquer thinner, you're probably going to mess up the area you just refinished.
What I just described sounds fairly straightforward but that could easily turn into 6 or more hours of mayhem and frustration with the possibility of ending up with something that looks worse than it does right now.
If you're not very comfortable and experienced with wet sanding and buffing, I'd just leave it alone. The most I'd comfortably do would be a quick wet sand and buff, and that would just be for a very modest improvement in appearance. To knock the epoxy down just a bit, which can take some of the harshness away from those lines, and buffing it out to a high gloss will help make it less obviously different from the surrounding area.
However -- the clearcoat looks very thin on that top, and even with a quick wet sand and buff with moderate to fine grit paper, you run the risk of going through the clear and color coat and exposing bare wood. That will be REALLY obvious, and at that point you'll wish you just left it as it is right now.
Some of my favorite guitars are beaters. My main acoustic these days is a cheap 100 dollar something or other that had the headstock broken twice, and was epoxied back on. And not cleanly! You can literally see gobs of hardened epoxy around the entire joint and there was no touchup work done at all.
But it plays great. It doesn't sound great and it doesn't look great, but I don't need it to.
I hate telling people to 'leave it,' but it's a rule I've violated more times than I can count to my own detriment. If there was a really thick clearcoat on there I'd say you could probably get away with a fairly aggressive wet sand and buff to at least blend that hardened epoxy in a little bit so it wouldn't look so obvious, but that can quickly go awry with a thin clearcoat. Don't ask me how I know
and I would move on.