Is the only purpose of "Bait, hook, reel, release" to see if you have completed A2(To see if your target has become interested in you)?

If "Bait, hook, reel, release" tells you that your target has become attracted to you, which means that you have entered A3, you still need to use other routines to qualify your target to you, just to answer her question on mind, "Why does that guy like me?", right?

We should use "bait, hook, reel, release" before A3 waypoint(So, how do you know each other), right?

"This is actually a false qualification because you’re not really going to be able to qualify her as LGF potential in 5 minutes." Does it mean that A3(qualification) usually takes 5 minutes?

Hey man, I will try to respond to your post piece by piece...
The purpose of BHRR is to increase your target's interest in you and to gauge said interest. You should BHRR throughout the sarge, not limiting it to A2, in fact it can be used as a tool to raise sexual tension and eliminate LMR before it even happens...
Yeap, you need to make your target believe that you are attracted to more that tits'n'ass... give her a legitimate reason why you, a high value male, are spending your time with her. Ever notice how when you over-DHV you lose the target because she feels she has no chance with you other than a ONS?
You should follow the logic of MM, not a rigid structure... A2, A3, C1 are stages of the interaction as you see them; you may have to come back from C1 to A2 if the target isn't really in C1. BHRR is a tool in the PUA skill set that can be used anytime when it is necessary...
No girl expects that you qualify her as a potential GF in 5 minutes; you qualify her as an interesting person to spend some time with, think of video games where the first levels are lame-ass easy and difficulty increases with the later levels; first hurdle: physical attraction, second hurdle: interesting person to talk to, third hurdle: some degree of connection, and so on...

Hope my response helped, good luck!

So if we think that we have possibly completed A2, should we say "So how do you know each other?" or should we use "Bait, hook, reel, release" first?

If I ask "So how do you know each other" and they don't tell me, should I go back to A2 and continue to DHV?

Quick question, why you're asking about when to use the "So how do you know each other" line? You don't have to use this line at a precise point, it's just a way to dig some info about a mixed set where you are not sure if the guy and gal have something going on, and it provides you with an elegant way to find out. I have never used it, as I rely more on observation of the interaction between the two people in the mixed set, rarely fails me...

After the target says something about her, and we indicate our interest in her, we should "release" or
"take away", or "throw an IOD", why should we do that?