Unless I am not understanding what you are saying, you are attempting to defy basic botany.
Hybrid plants never seed true...if indeed the seed is viable.
Rocket snaps are hybrids, don't know about the liberty series, but I suspect theya re also hybrid. But left to their own devices you will get 100's and 1000's of plants and while not true, they will be interesting and attractive....and eventually after several years they would all revert to pink, because that's what bees prefer. To prevent cross pollination, you would have to enclose the flowers in a mesh fine enough to prevent an insect large enough to pollinate a snapdragon from entering.
But you still wouldn't have them breed true, because to do that you have to make the cross every time you plan to harvest seeds.
Linda C

that is what I figured. But I had to ask. Thanks.