If you bought them only six months ago you’d be fine. I replaced a tire after a year of driving the new set and had no issues. If you’re worried you could measure the tread depth of the old ones to confirm they have most of the tread on them.

Might be worth getting a realignment also if you hit a pothole that big. That will make sure you don’t have any uneven wear issues in the future

I might be wrong, but my understanding is that wheels connected by a differential need to match or you'll cause extra wear on the diff/transmission and possibly jerky driving. Since your car is FWD, just make sure the front wheels match. Honestly 5k is hardly anything assuming you don't hoon. I wouldn't worry about it

You'll be fine. Maybe put it in the front left (if in US) since that one generally wears the fastest if you drive spiritedly.

Depending on where you live, you may be able to locate a used tire shop nearby that has a one-to-one replacement for the one with the bubble, but as @simulacra_simulacrum@lemmy.world said, six months and 5k should mean your bad tire is still basically new, and you shouldn't have any issues replacing it with a new one

Personally, I'd replace the problem tire and swap it with the front left at best. Depending on how many miles I've put on it and how bad the wear it may not even do that.

But that's just me! There are some folks on here who know much more than I so I'd let their advice supercede the above. Drive safe!

Since your vehicle isn't all wheel drive, you can, easily.

Just keep the new (or new used) tire on the non drive wheels (so the back, for you).

Basically, you just never want to have mismatched tires on drive wheels. You'll wear stuff out on your vehicle if you do. Expensive stuff. Not the cheap stuff :-/