I wouldn't say meditation in the terms of thinking nothing but more the kind of meditation where the hands are busy but the mind is free to think of the things that have perhaps been set aside until a more appropriate moment comes.
Animal models? Yes, at least in the early stages. Certainly in potions, we use animal models if the potion uses some of the more dangerous ingredients. Basically to test whether the levels are too high. But inevitably you do have to move to human test subjects. And if your potion or spell will not work on animals, human subjects are required.
I haven't used it much with my potions. The internet has certainly been a useful resources for locating various ingredients.
Muggles can enter memories but I'm not entirely it would work. I can read the book because I have read it in the past. It's worth trying but I couldn't tell you whether you read a book with text or simply find a book full of blank pages.
I think I would have rather used it for those purposes, except I preferred to avoid the Ministry as much as possible and family dinners were... never a thing for me.