I have heard before to break up the root ball from potted plants/trees, every time I have done it the plant/tree has died. The ones I just planted did fine.
You can really only do this (aggressively) when it's dormant and way before spring. You have to be careful on breaking roots and then you have to make sure and slow water (flood) it to get the air pockets out. Plant it high so when it settles the trunk flair stays slightly above ground level. Keep it watered and it will do fine.
Yup. Plant in the winter.
Last three trees I planted were on Feb 1. Months later than I wanted to, but I was walking by them, and bought them. Opened up the roots, being careful with them. Feb 2, they got covered in ice. They bloomed mid-May and are still doing good.
5 gallon bucket. Drill an 1/8" hole in one side, at the bottom. Fill it with water and the little 1/8' stream slowly soaks in. But I do give them a 30 second run with the hose directly onto the ground each time I water. It is a peach, plum, and pear. They've been getting watered around 8 pm every four days or so.