Advice request: potentially adopting a cat

My wife and I are potentially adopting a cat.

The cat is an adult, not sure the exact age (but will see if that’s known when we get it).

The long story short is, a close friend had 3 cats (I think strays as kittens but not 100% sure, I think they were acquired at different times - they do not appear to be related to each other), but due to the current political state of the US ended up moving abroad on a visa for this past year, and is planning on staying away for longer. Initially, the cats were staying with another friend but that has recently fallen through (I think they did not expect the 3 cats to be as much to handle as they are, they keep getting onto counters, eating food that is left out/left unattended, and scratching furniture, and at this point they’re getting fed up with them), and we were asked if we could take any of them

We have met the cats quite a few times, and they do seem friendly towards us.

My wife seems very allergic to one of them, but only mildly allergic or significantly less allergic to the other two.

We currently live in an apartment that does allow pets, but this would be the first time either of us have owned a cat, so unfortunately I think we could only take one of them.

I’m thinking we could probably use some advice on things to consider and best practices.

Preliminary research has said to get 1 or 2 litter boxes, feed at regular times, running water bowls are preferred, and get lidded trash cans. We plan on keeping the cat on the same food and litter type, at least initially. I know there are other things, and we will take the cat for a check-up and establish a vet. Due to my wife’s allergies, we are planning on keeping the cat out of the bedroom and running an air purifier there, and hopefully visiting an allergist before we adopt the cat if time permits.

But I’m wondering what others’ experiences have been with a cat in an apartment and what advice you may have? (How to keep them off of counters? Keep them from getting bored while at work or while working from home?)