Okay, thanks for the pics. Here are some additional thoughts:
The Brown Bass is custom.Looks like it might have the addition of a master volume control and it has an extra toggle, probably for neck LEDs? Looks like a pretty nice specimen. A back photo would confirm the LEDs, as could the owner by flipping some toggles. I would probably ask something in the vicinity of $4K, maybe a little higher.
The SC has a large body inlay that could use a close-up photo. Otherwise, it looks pretty stock. That inlay could affect the value, possibly negatively. I can't tell what it is at this resolution. Maybe $3000-3500?
The Series is actually a Series I, not a Series II. It looks to be pretty old and generic, plus it has had the tailpiece moved. At one point, there was a special cable and a small blue electrical box that were paired with this bass. If they are missing, replacement can cost several hundred dollars. In addition, a bass of that vintage could need a trip back to the factory for electronics cleanup. Probably $2500-3000 in this shape and without the electronic parts.
If it hasn't already been done, all the back covers should be removed to check the health of any batteries left in the instruments. You don't want an old battery to fail and cause damage in there. Also, be careful if/when you sell these. Especially the older two. The older cases are fine for local use, but the foam may not be sufficient protection for shipping company transport. You may want to bubble wrap the instruments inside the cases for extra protection.
My value estimates could easily be off by several hundred dollars. These three instruments all have features that make them unique in a way that could affect their value to a subset if the market.
Good luck!
-bob
