Yes, any non-barred male crossed with a barred hen will create sexlinks. All male chicks will be barred (and have a headspot), and females not barred (and have no headspot).
My experience with selling POL pullets in my area is that I can get $5 more per bird for purebreds/desired breeds than...
Yes, this.
Offhand, I'm not a bantam person so I'd stick to the LF rooster and the LF ladies.
If you're just enhancing your own flock and don't plan on selling chicks/started pullets you could just pair the chosen rooster with whichever hens you like best for whatever reason you happen to like...