I'm aware the game is universally lambasted but I'm having so much fun with it.
I was battling some woman and a group of five smolives walked by in the background and I noticed one of them had a black olive instead of a green one. After I won against the woman I ran up to the little one with the black olive and it was indeed a shiny. I named her Madeline.
The woman in the city who rates your pokemon's size says I have the thiccest jigglypuff she's ever seen.
spoiler
Sending out my tandemaus couple for the hundredth time only to find that they've started a family
is probably the most fun surprise I've ever had playing a pokemon game.
In my experience yes, although there's an auto-battling feature that I haven't used. I imagine if you have that going most of the time you get a good bit more exp than I've been getting.
Use the auto battle for getting the materials to craft TMs
A Pokemon will stop auto-battling and flee if their health goes critical, kind of like the Wimpy value in old MUDs. This is how I learned why you don't try to level grind on Squawkabillies.