I think it just depends on what you're used to. I'd always had the hamper style, but my new dryer only came in the side swinging. It took me a couple of weeks to get fully used to it, but now it's fine. It is easier to get things out not having to lean across the door, but I also can't just throw wet clothes on the door and then shove them all in like I did before. IMO, it's not really that big of a deal either way though.

Time certainly flies doesn't it? Why bother? Well what if someone finds the thread the same way I did, would not discussion be just as valid? Another tip is a drop of muriatic acid on the pin. It cleans out any lubricant and roughens up metal. Be totally aware: Muriatic acid and water make for powerful, caustic, and harmful vapors. That is why I suggest only a drop. Use only in a well ventilated area. Although it will burn your skin it is very effective. .

Closing the gap would mean the door would not open and shut properly. The astragal is the best solution other than ignoring the gap. If you just moved in ignore it for a week and see if it matters... The convenience of no astragal would win for me

I would use regular hinges for the new, solid doors as they can handle more weight and will hold up for years without needing adjustment compared to things like Euro hinges in this application. You don't need more than three hinges. Your new doors may already come with the hinge mortises completed. In any case, it's unlikely that that the holes in the new hinges will line up with the existing holes in the jambs. As for catches, quality ball catches that are adjustable will work fine. Cheap, nonadjustable ball catches are a poor choice, and that is probably where your bad experience comes from. I have ball catches on a pair of doors into my laundry and my two pantries. They're 20+ years old and still function effortlessly. This is the type of design you want where the ball can be screwed up or down for a good fit: Adjustable ball catch