FLCL
I like WhiteDMist's idea, but Roselia even with maximum investment and Eviolite is actually a bit on the frail side, and people are unlikely to let their Tspike absorbers go so easily. In addition I found the tier a bit too offensive when I tested it for it to do its job effectively, being 2hkoed by almost everything I wanted to switch it in on when running Ebelt, and rarely actually eliminating the opposing grounded Poison. No one actually switched out with whatever I switched Roselia into bar Alomomola and other walls, they just smacked it and without Eviolite it died.
Specs Roselia sounded great until I tried it, then I immediately started to wonder why I wouldn't just use Vileplume to similar effect. The far superior bulk easily outweighed the lack of natural cure, while having the same suprise factor. It's a cool idea if Vileplume isn't also in the tier.
Anything that's either not running hazards or not running Eviolite troubles me, as that is Roselia's main niche over the otherwise bulkier and more useful Vileplume
FLCL's set proved more reliable as a whole, and also included useful recovery in Rest, so that will get my vote. After all there's a reason Garbodor is nearly nonexistant on PO, and that's because Roselia is so ridiculously effective with this exact set.