Rendolf

Man you were able to beat Charlotte on your second try in your first playthrough? She is quite possibly the hardest gym leader out of all of them so good job for that

It's hard to say. I'm sure at least some fraction of them will be coming back but who knows. Depending on which routes you took there are also some other people in sorta similar scenarios, so we'll see.

Should be a visible Poke Ball. If you can't find that then the other way is on the 11th floor of the Department Store, but you don't get that until towards the end of Episode 18.

You can get one on Route 2, past the Celestinine Cascade.

Steel was my first too and I had a pretty easy time with it (Shade was a pain though, even with my Pawniard god roll)

It costs 3 heart scales to change natures, so make sure you have at least that many.

Good to hear!

Apparently if you hatch an Iggylbuff egg in the (upper) Peridot Ward then you can give that to her I think (Or at least I've heard that sort of thing about other returned Pokemon so I'd assume it works here, too).

One thing you'll definitely want is a Ninetales for its Drought ability, so be sure to find all the police officers and hope you get lucky with a Vulpix. If you don't get super lucky with a Vulpix then be sure to catch a Stunfisk once you get to Apophyll Beach, you'll need it for later. Torkoal also gets Drought so you can get one of those too, but it isn't available until much later in the game.

That's weird, I'm not sure why that would be the case. It should get it according to Bulbapedia.

Yeah I was gonna suggest going to your last backup if it wasn't too much of a hassle, glad it worked out. Just keep at the battles, you'll get there eventually, and just know that this one isn't the hardest gauntlet you'll have to face...

Obsidia Park, 20% chance any time of day

Sure thing

Well actually when I say Thunderbolt is available I mean that you can get it just before the last gym battle. So you might have to survive on Discharge for most of the game haha

Nope, sorry. Thunderbolt is available eventually, but since you specify Galvantula I'm guessing you intended it to work with Compound Eyes...

You get Kantonian Vulpix from a trade for a Stunfisk and you can't go catch one once you gain access to the trade.

The no over leveling rule isn't really necessary because in Reborn if you get higher than the level cap your Pokémon won't listen to you. But if you want my honest opinion, the game is already hard enough as it is the first time through so Nuzlocking it is kind of overkill. You're pretty much guaranteed to lose battles even without these restrictions in place, and having to restart the entire game on top of that would just be a total pain. That's just my two cents so you're still welcome to do whatever you want.

I think that the ability to check your relationship points like this is a feature of a mod, I'm pretty sure there isn't any way to normally check them in game.

Some tips for each of your members. Politoed: Seems pretty good, although having both Toxic and Perish Song feels redundant. You also might want to train Special Defense rather than Defense, but that's up to you. Mantine: As was said above, Mantine doesn't get Hurricane in Gen 7 and Ice Beam as a TM is not yet available in Reborn, so you'll need to swap out those moves. One thing I definitely recommend you have on it is Roost. Mantine got Roost in Gen 7 and it was a godsend for it, pretty much if you're running Mantine you're running Roost too. Also you get Leftovers pr

My guess is that it would either stop you from progressing or do nothing at all, depending on how the devs coded it.

Voltorb Flip is the way to go imo. Once you figure out how everything works you can get a lot of them pretty quickly.

You can get a Shinx fairly easily from the Onyx Game Corner

Both are first available in Tanzan Cove, Mantyke after visiting Spinel Town and getting the Good Rod. This is a little while after you get your 5th badge and right before you get your 6th.

Empoleon has always been my favorite!

I would agree with this except swapping Meowstic for Swampert, it's your only ground type and psychic is already covered by Metagross, plus water/ground is a pretty great typing. Actually, it might kind of depend on which gender Meowstic your's is, since one is a bit more useful than the other.