I don't think the book specifies on this subject, but I may be wrong.

Character A delays their action past the end of one Init Pass into the begining of the next.

Character B spends a point of Edge to "Go First" in the Init Pass.

During Character B's Declare Action Step, Character A declares they want to use their delayed action to intervene.

What order do the actions resolve in?

My interpretation is that the intervene action, essentially being a holdover action from the previous turn, allows them to surpercede turn order. But the spent point of edge allows the character to essentially violate turn order cause dey so awesome. So I'd let the person who spent edge go first.

i would agree with platonic.... i make it a rule of thumb that anyone that SPENDS something should have the upperhand in a tie.

Ah, but if you delay action in one Initiative Pass into the next Initative Pass, really, you're "spending" one of your actions, because you only get one action per Pass.

Of course, Edge is a much scarcer resource than a delayed action. You get at least one action that you can choose to delay into the next pass each turn. Edge refreshes a lot less frequently than that.