Heart Mug

If you search for "microsoft visual c++ runtime terminate in an unusual way" you will probably find a solution. But here is a video that might help.

The bug has been reported and might be fixed in the next update. Reloading an older safe is probably your only choice right now without using debug mode. Or you wait for the next update and hope they have somehow fixed it. The only silver lining is, that waterfall is currently unusable outside of battle, so at least you would not miss out on anything. I am sorry, that I could not provide a more satisfying solution.

Yes they work.

No your are not using them wrong your pokemon just receives all stats it would gain for multiple lvl ups with the first lvl up.

Unfortunately, choice scarf is not yet available in v13.

I found 5 so now you have 101 cells. Game.rxdata

The earliest location you can get a Petilil is in Grand Dream City. You get access to GDC after 10 badges, and by the time you get there you should have a sun stone already. If you need more information on Pokemon or item locations check the guides & resources tab. https://www.rebornevo.com/forums/forum/208-guides-resources/

Yes you can buy it in the Underground in Grand Dream City. You have to accept the Help Center Quest Missing Children in order to get access to the Underground. However once you reach Grand Dream City you will not be able to return to the other places you have visited for quite some time.

It is from Pokemon Ultra Sun and Moon

You need strength to get to sneasel. So no, you can't get one before the sixth badge.

No

This it the pickup table for Rejuvenation.

It's a bug the new patch 13.0.4 should fix it.

I think you have to download the entire game again to get the 13.0.3 version from the devblog at least that worked for me.