I’ll add my cents for some of these:
Both of these are dependent on your local conditions/disease pressure and issues. Also, if you’re grafting to trees that are already established or grafting, then planting the trees out.
I have to spray certain non-bearing trees (including newly grafted) or they would be destroyed by fungus or pests. My disease pressure is pretty high and it is humid here.
I also fertilize in spring for established plants (newly grafted or not). I wait a few weeks after planting to fertilize a new tree or plant. However, my soil is such that I really need to fertilize. People are nervous to fertilize apple and pear because of fireblight (I have no idea if that is a problem where you are). However, for my conditions most of my trees need some help.
I have grafted outside at some very non-optimal times.
I have heard persimmons are a bit fussy. So I’d look at the threads specific to grafting persimmon for info about them.
For apple and pear, I grafted in early June (2-2.5 months after it should have been optimal) with dormant scionwood to established trees outside. I was careful to wait for days that were not too hot (which prevents callusing - and there are a bunch of posts with callus temps). They were fine. The biggest problem was that they missed the big flush of growth. They didn’t grow much in the first year. I didn’t notice less success, just really slow growth.
I also tried some late peach grafts with dormant scionwood last year. I think they were doing well. In fact, I think I had a higher success rate than grafting at a “good” time this year. Unfortunately, a guy with a tractor ran over a couple of my trees. This year, I’m not yet sure of the outcome on some. So I don’t really know which was better.
After some period, it is better to switch to non-dormant wood. I can tell you that I kept using dormant wood and even chip budded a pear with some really old stuff in my fridge in Fall (But pears are really easy). I tried the same with pawpaw and failed. Never tried it with anything else.
Here are some threads on that: Technically there is no end to grafting season. I have done t-buds and chip buds in late summer and Fall to peach and pear with lots of success.
Clark tried some fun crazy stuff grafting in the middle of summer and really protecting the grafts from heat and it worked: Late season grafting experiments only. Using green wood cuttings, Plastilina, tbuds, chips, and other methods. Pears are super easy though.