I apologize for this delayed reply to your gardening question and hope it is still helpful to you.
Protecting a large tree is not practical but a smaller tree can be covered with a tarp placed over a PVC pipe structure and then a heat source placed inside.
Your options for propagating those fruit plants include cuttings, air layering and grafting. The following web site offers tropical fruit propagation info:
This next web site shows how to cleft graft avocadoes. This method works with most other fruit trees as well.
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!
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