Mag Chat, mag love? Options

[Dive]

I am raising a new mag that will be a pow mag for Harbinger. I have a current pow mag but it lacks the Mylla & Youlla PB. Chaining PB's seems to be quite popular now and very usefull in the tougher areas. It's rare that someone in the team doesn't have the Twins, but it has occured, so I am making sure that I at least get it. So I have a couple questions for you Mag Farmers.

What in your opinion is the best mag to have for a melee Force?

If I use a Cell on a mag before it learns all 3 PB's, will it learn them later?

Does it matter when the mag learns Mylla & Youlla? Does it make a difference where the PB is on the buttons?

When doing a 4 way PB Chain, which blast is best to do first/last to get maximum Shifta/Deband boost?

I ended up with the Leilla PB because I didn't plan it through before hand. Can this be used in a chain without dire effect on the S/D boost?