Avi is a pureblood so if she develops more and gets her own pieces she may take in the other 3.

You're right, I could see Avi making her Peerage with Junior's Cast but then wonder who could be Rias's New Knight and Bishop?

Inconclusive.

There aren't any known characters who would be good for her

Valerie would be more likely to join Gasper.

And that's basically it.

2 handsome guy just to make Ise jealous.

Not likely.

Any male Rias gets that isn't Issei doesn't have an active love life or anything that could make Issei jealous.

Kiba/Gasper/Loup

Also why would ise still be jealous now

Exactly. he's protective of his women and their oppai, but not jealous

I'm thinking about the possibility that Xenovia's Knight would Lilibette D. Lunarie and her Pawns a Maou's Descendant considering Ishi's liking for her and that she want people with particular situations

Lilebette would make a great Knight but any Junior characters joining down the line is low on the probability scale.

They aren't appeared yet in Shin, but maybe once Ishi could be able start to writte again maybe he could considered that to use the Junior's girls.

If Junior's Girls would appear in Shin and would be involved with Main Cast the popularity of Junior could be increased.

I wouldn't bet on it.

Junior case mingling with main in Shin is welcome but improbable. And at this rate even with this new content, Shin remains in the air. If the Slashdog team can join the fray, no rule against Junior squad. A lot can happen in a years time frame.