At least two of those minis are currently available on Ebay right now, without an archive fee. Don't be afraid to shop around.
Yeah, yeah, yeah, you want to support IWM. Is making them drive offsite to grab four molds they don't normally use, heat those molds with multiple castings that consume lots of time, energy and resources, and distract them from other work just so you can get a lousy four miniatures really the best way you can think of to support them?
Note, I'm using the colloquial "you" here, not addressing anyone in particular. I'm just tired of that argument.