I would try Mod Wiggler or Elektronauts. I sold a bunch of non-modular stuff recently and Elektronauts is a pretty large active community of people who are likely to be interested if you are motivated to sell (read: priced to move). Be prepared for some trade offers though, no matter how much you tell them you want out.
Yeah, Rean is Neutrik’s consumer/lower priced option, Gibson’s Epiphone if you will. I’m sure they’d be fine. Probably anything would be fine. Once you walk away from the Planet Waves marketing hype that this stuff will make you sound like a rock star, it’s really down to build quality, and I think for a bedroom setup anything that conducts electricity will work. If you’re making a living on stage night after night with beer and sweat and stompy feet, the real nice robust ones make sense. Otherwise I’d err on the side of cheap because they just won’t get much abuse. Even $0.60 AliExpress specials will stand up to the normal wear and tear of a bedroom studio because they’re mostly just hunks of metal.
If you haven’t, check out Redco audio. I’ve ordered from them several times to great success. They’re usually price competitive and have wonderful customer service. Mouser may still be the better deal these days but worth a look.
As far as soldering and irons go, temperature adjustment is nice but not mandatory. You usually want a good sized puddle on the ground which is made easier with some extra heat.
Don’t use the tiniest tip in the box. None of these things are heat sensitive like electronic parts so the faster you heat up the faster you’re done.
Do yourself a favor and don’t get lead free solder. It’s awful to work with. You’ll also want a sponge or brass wool.
If you’re doing a bunch of these, invest in some helping hands. Even the cheap $5 one from Harbor Freight is better than nothing.
Test continuity with a multimeter while flexing the cable.
Look up what a cold joint looks like and be prepared to fix them. You just need to reflow the solder, but if you don’t you’re going to have a bad connection that looks fine at first blush.
The biggest piece of advice I can give you specifically for cables is when you’re doing the second end, make sure to slide all the backside crap over the cable before you solder anything, for obvious reasons. Even though I’ve told you this, you’ll still miss it once or twice if you do enough of them. It happens. It’s a great chance to practice more soldering.
Relevant to our interests, the Zoom Livetrak L6 digital mixer/recorder $299
I second everything that @Artificer has said about soldering. Especially lead free solder. I think a decent soldering iron makes the job easier. You don’t need to buy the most expensive one but, just don’t get the cheapest. Use a pointy tip, not a flat tip.
Make sure you have somewhere safe to rest the iron when you’re not using it, because you’ll be picking it up and putting it down a lot and you don’t want to burn your desk or worse.
Puncturing a cardboard box with the tip while it’s hot is the quickest and easiest way to clean solder build up from it. I like doing this instead of using the brass wool.
It’s funny, the less time I have with my synths, the more I notice all the little friction points in my setup and discover things like this.
Seems like the perfect time to set something like this up since I’m going to be making those new cables (ordered everything last night and expect to start next weekend, shipping permitting) and upgrading my interface to an RME UCX II with the money I got from selling synths (nothing against the my 18i20 btw, still works great I just have lusted after an RME for years).
I’m actually even thinking about rearranging my rack, I have the patchbay on top right now so that I can read top mounted labels, but if I put it on the bottom I can patch cables into the front inputs of my interface without getting in the way of anything. Small victory I suppose.
also, thanks @Artificer for the Redco suggestion. I saved like $70 getting my connectors from them instead of mouser. Really helped with the budget on this endeavor.