We used these videos this year for pruning:

Peaches:

Plums: https://www.wilsonbrosgardens.com/how-to-prune-a-plum-tree.html

And these pictures:
Peach:

We'd not pruned them since the year after planting and the older peach especially was very bad last year. I wouldn't just top them, but use the guides to promote healthy growth.

I cleaned the grass away from the bases for quite a ways then put down wood chips pretty thickly, making sure the chips didn't touch the trunks. The comfrey won't do much for the grass, in my experience. I have it around many of my trees.

The leaves around the base of the elderberries looks more like brassica leaves than elderberry...

I think with pruning, and maybe feeding the little trees would do well. But pruning is usually only done in the winter when the trees are dormant.