Not feeling the .410 as “essential.” Pest control is about all it is good for, and I can’t think of many situations where you wouldn’t be better off with either a 12 gauge or a .22. For snakes. I’d probably just go with No. 8 shot from the 12 gauge—if my neighbors freak out about me discharging a shotgun, then I doubt they’ll calm down if I say “Don’t worry, it was just a .410.” If I really want to use small shotshells, I keep some .45 CCI shotshells around. For armadillos, either gauge birdshot or a .22. I have a friend who uses a pellet gun pretty effectively.
Try "Sorry. Next time I'll just shoo the rattlesnake into your yard."
Rather than a full-size shotgun, a wheelgun in .45 Colt makes far more sense to me. Alternate .410 with .45 cartridges, everything he calls for in a varmint gun with the added advantage of a serious stopping round available at will!