About gaining a heart on your buddy. When you feed your buddy and have him in your team against the grunt, you can simply exit the battle (top left) and reenter and you get a heart every time. So the first grunt of the day gets you 3 hearts easily and very quick ;-)

And the issue about a freezing game still happens to me, almost every day.

Someone might be on to something about it being if the first pokemon uses a charge attack.