I would use a good carpenter or wood glue. You don't want to use anything that cannot be undone in the future, particularly if you don't like the way the joining looks after you're done. I would do a quick web search for furniture restoration techniques before you start out to see the best way to clamp the leg while the glue is curing. Also, any filling that needs to be done should be done after the gluing process with a proper wood filler, not with an epoxy. Anyway, that my 2 cents for what it's worth, and that's about 2 cents.

Paste wax is the "polish" of choice for me....and that will likely make the scratch in the finish pretty much unnoticable.

That's tough as the veneer has lifted. If you sand it down it will look worse. I suppose you could use a thick poly pour on top but you will still the lifting beneath the pour. Quite frankly I cannot think of anything else you could do other than laminate a new top over the one you have and then it might not match the chairs. You might consult a local furniture repair company and see if they have some suggestions. The isue is how much money do you want to spend working with the table.

My husband says that it is the color of old copper. I am not getting the spelling right, but veridis or something like that. For those who don't know. My husband and I build furniture for other people. Very high end stuff. We can not afford our own stuff. we can't afford the materials . So normally we make do with out, or we scarf something from goodwill, the metal junkyard, or craigslist. We have furniture made of all sorts of junkyard trash that has been repurposed. It is a case of the cobblers kids without shoes. The chairs came from HEB while we make chairs for the Neiman Markus catalog. HEB is stepping up for us. This table came out well. I think I will pull up to that sea of reflection and mar that perfect surface by doing my bills out here today after coffee.The weather this morning is beautiful.