I will not hesitate to bet on Pacquiao if he will be indeed the underdog of the fight, odds does not determine their chances, we are talking of the legend here who beat an undefeated fighter, who knows, it will become 2 in a row to beat an undefeated fighter. +300 odds would be a nice one, Ill take it all day.
Many people do not like Pacquiao's chances on both fighters but we never know, Pacquiao's power and skill never left him for the last ten years but the two fighters are in the different league, we know Pacquiao he never backs out on any fighter so it all depends on their respective promoters and the shares of the profit, we will hear more news if a fight with any of the fighter will materialize.
Pacquiao himself is his own promoter, he left the top rank promotion to make his own, so that means he can fight any fighter he wants, he already did it with Thurman which is a solid fighter, so I have no doubt he can do the same on any champion in the same division.
Spence and Crawford had already defeated their opponent this year, they have proven themselves they still have the discipline to maintain their body and skills, so maybe it's time for the two to fight, and definitely Manny will take the Winner.
A spence vs Crawford fight might generate big money, but a Manny vs Crawford or spence fight, will generate more IMO.