Answer: Most avocado trees have grafted varieties on vigorous rootstocks so exactly where the shoots or suckers are emerging is an important consideration. You didn't say how low on the trunk the trees were cut; perhaps high above the graft union, but there's a possibility that they were cut below the graft. So, I don't know if the new growth will ever produce fruit, but at the very least they will make attractive shade trees. How much water and how often really depends upon the size of the tree. Root systems typically extend out past the canopy of the tree. Without a canopy, it's hard to guess, but the roots are still there. Because old trees have extensive root systems you may not have to intentionally water the trees at all. Whatever else gets watered in your landscape will probably provide enough water for your avocado trees, as well.
Wish I could be more specific!
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