Imagine if they release Scrappy before Scooby, wow things would get rough!
Luckily we know that's not the case- Scooby's coming in wave 2, unless they pull a fast one on us. It would be like ol' Scrappy to come in at the last second and muck things up.
I could see wave 4 going either way with Fred or Velma. Considering her popularity, they may want to get Velma out last to get people excited. At the same time, regarding Fred, I can see them both wanting to get him out next to complete the Daphne/Fred duo, but also waiting until last to keep people both interested, and to end the base gang with their de-facto leader. I ain't gonna be mad either way, as long as we do get the whole gang. I wonder how many people are waiting to invest until we get confirmation everyone is coming.
As far as the price goes, I was a little hesitant at first, but, like others said- it really doesn't feel that bad. The franchise is instrumental in the story of "Me", and for the price, you really do get some heckin' nice figures. Great articulation, great unique sculpts, clean paint, fun accessories. I was really kinda taken by the small details- how the pants continue on past the top of the shoe, the hanging bits of wrap on the Mummy, the mid-unmasking stretchy mask on the Creeper, etc. Perhaps most importantly- Shaggy's hand that can actually hold the Scooby Snack; it's one of my collecting pet peeves when a company includes a hand specifically for an accessory, but they still can't hold it (NECA's recent paper accessories being my latest frustration). It's clear that these are made by fans of the series, not just a company looking to make a quick buck, and that I'm happy to support. If nothing else, wait for a sale, but as others have stated, they're really not much more than many other lines nowadays.