If you don't trust that, just try to construct a recipe that includes the doll you want and as few dolls as possible that you don't want. You can use the wiki page to see the requirements for each doll.
Grizzly can be gotten with just 30/30/30/30 for instance, if you use that recipe the only 5* dolls in the pool are her and Thompson.
Type 97 requires 30/400/400/30, if you raise one of those 30s to a 91, you'll be using enough total resources to remove HGs from the pool (or you can leave them in for the chance of getting Grizzly since you're looking for her still)
Negev requires 600/600/100/400, there's not really anything you can add to that to remove other dolls from the pool unfortunately.