Best arborist practice says ammend the site, and then plant the tree in native soil. With mulch once a week will be MORE than
enough. I tend to allow for some real dry down toward the end of the summer to encourage downward growth of roots. The tea-cup effect (where roots circle the hole rather then venturing into native soil) will be reduced because sandy soil doesn't provide teh impediment to
root extension that clay soil does.
Putting to much organic matter in or under the tree is risky, because the organic matter will subside as it decays, lowering the crown of the tree.
I just avoid burying the crown in wood chips (although many species don't mind, and just form adventitious roots). Unless I have a vole problem, that is all I worry about.
Some of the trees you suggest are so robust that I wouldn't worry to much.
Finally - smaller stock will typically establish faster with less watering and transplant stock (if you can control competition), so buying big trees doesn't necessarily help.
Good luck.