Believe it or not I personally don't really care that much where Lanturn goes, both C and C- are fine for it. I guess the rise of Spikes Greninja is a big problem for it, but Magnezone is still very common from what I can tell (or maybe that's just ORAS) as is MMane so still holds a pretty valuable niche (also I would never run Lanturn without Hell Bell, the team support is just too good to pass up)
btw here's an okay Lanturn replay, not really that good but if anyone should have Lanturn replays it's me :
http://replay.pokemonshowdown.com/ou-170597512
I did end up losing since I decided to spin on Keldeo instead of Recovering like I should've which basically cost me the match, but I think this replay kinda demonstrates what Lanturn does best which is preventing Volt Switch from ever happening. The MManectric user was more more-or-less forced to double switch most of the time he sent it in fearing Lanturn coming in for free and even getting health back in the process. Since I was just testing Lanturn out at the time wasn't fully aware of what it did I didn't really abuse that fact a much as I should've (though I did take advantage of it a little bit keeping Talon in on MMane in a couple situations), but yeah that's basically what Lanturn does.
MHera definitely deserves A+, it's a really powerful wallbreaker that's also pretty good vs offense, at least, better than most wallbreakers in the tier thanks to its solid bulk (also anyone who thinks the the lack of speed matters much against offense is wrong : it really only matters vs bulkier teams where you have stuff like Mew and SpD XZard creeping it). I guess the slight drop in usage of sand makes it a bit less good but in return, Bisharp rose in usage and also threatens a lot of teams which is good for MHera because it's one of the best countermeasures to it. Oh, and unlike, say, MMedi and MGarde, none of its counters really fit that well on anything else than Stall, (Jirachi and MZor and Slowbro and Mew vs what, Unaware Clefable? Acroscor maybe?) so as a result it's much better vs balanced teams than most wallbreakers too (also the sub SD set is fantastic, please use it)
I can see why you'd kinda want Garchomp to drop because it doesn't really come off as being particularly great, but I feel like the combiantion of bulk, power, typing, speed, and setting rocks, despite none of these aspects being stellar, is just good enough to make it A+.
I've used Rhyperior a lot recently and although it is certainly good and kinda underrated, it has a very glaring flaw in that fact that it lacks reliable recovery. Due to its huge physical bulk it doesn't get worn down as much as other defensive Pokemon that share this trait, but the problem is still there. Also, Rhyperior pretty much needs cleric support since it's extremely vulnerable to Toxic and especially Burn which quite a few things it's supposed to counter (Talonflame, YZard, Victini) commonly carry . It's a great addition to a team but it needs a bit too much support for me to see it in B+.
I'm really not sure what Zapdos does, it's a mediocre defogger and it's too slow to be a proper birdspam check.
Quagsire I used to think was garbage post-Mawile but it has a niche over Slowbro in the fact that it completely cockblocks electric types so it's not as bad as I though it was but eh, it's still worse than Slowbro/Mola most of the time and i'm still not sure it should be as high as B-.
Zygarde is actually a bit underrated, it's decent on stall for countering Bisharp and Excadrill but it's still an inferior option to Hippowdon in most cases since it actually deals with Electric types worse, and obviously lacks reliable recovery, so idk. Could be an option over Hippowdon if you want a win condition for semistall stall or balance I guess, but reliable recovery>stat boosting on defensive teams generally.
I have no idea what the logic behind Blissey rising is since its niche over Chansey is less valuable now that Lando-I is less of a threat in general, and Chansey also got worse to boot.
Toxicroak is pretty underrated, I've seen it in action and it's definitely better than C.
Cobalion is also underrated, it has a solid niche and a nice set of tools (SR, Volt Switch) which sets it apart from its competitors, so C+ seems good