Very useful post.
I did not know these details about how complicated some seeds can be.

you need to place them in the fridge for a month or two to give it that winter hardening that it would go through out there in the wild. Some needs to be placed in hot or cold water for 24 hours for the seed to swell up and then placed in cotton / soil in the fridge / window sill until the seed grows roots.

I have not tried to dwarf a plant to the point of turning it into a bonsai, but Ifor many years we were able to transform some considerable big trees that were planted in a square in front of our house into decorative bushes not taller than 1meter.
Constant pruning did the trick for us. But it would be great to have a huge tree in bloom frozen in a small version of it in our living room or garden.
I have tried propagation by branch of some trees, but it has not worked. Like the propagation by seeds, it seems that some branches demand cetain tricks we don't know about.