Bava Batra 48: Tavi, Paphi, and the Kinara

Rav Huna talks about a case where "they hung him up" -- to establish the duress under which a transaction might or might not work (Rav Huna says it does, even under duress). How does this compare to divorce? To sacrifices? Also, delving into the "hanging up of a person" - or suspension, which was done on a tree or about a shrub, to establish that coercion to effect a sale. Plus, how is that "duress" impacted by a preemptive declaration to prevent a sale and/or a bill of sale?