I will try to answer some of your questions. I'm a beginner and I recently planted 2 dwarf peach trees, a multi grafted pear tree, and a 5 grafted semi dwarf apple tree.

I've never heard of dwarfs being less tastier/sweeter than the normal tree. Of course, since its a smaller tree, it will have a smaller yield and unless you thin the number of peaches per branch, you'll get smaller and not as tasty fruit with it. But this applies to standard sized trees as well.

As for variety, I bought the July Elberta from Stark Bros. I've read many reviews saying that its really sweet and a good thing about it is that it has smaller pit compared to other peaches, so per fruit you get more flesh and less seed.

I'm not sure about the genetic vs grafted fruit trees so I'll leave that question alone.

Augustina, your rootstock will define the size of your tree. So, pick varieties that do well in your area, then try to find those trees on more dwarfing rootstocks. Pumiselect is very dwarfing rootstock often used for peaches/nectarines/apricots/plums. I have two trees on Pumiselect, a Weeping Santa Rosa plum and a Blenheim apricot. The apricot is going into it's 3rd year in the ground, and it is still quite small. If you can't find trees on Pumiselect, then the next best choice would be Citation rootstock. So, I would find a nursery that has the option of putting their stone fruits on very dwarfing rootstocks, then pick a good variety of peach or necatarine for your area. They can adapt well to container culture, we have one forum member (fruitnut) who has done phenomenal things with container stone fruits. I believe most of his trees are on Citation.

Patty S.