Have you guys ever encountered four-Reinhardt teams anywhere?

I was thinking of making an all Reinhardt team for the memes lol just to piss people off

Easy.

Myrrh bodies Reinhardt meanwhile H!Myrrh bodies WT!Reinhardt.

As cancerous as it sounds, four Reinhardts isnt really more difficult than one. There was a time the meta was deeply messed up by Reinhardt, and the way around it was basically making a dedicated Rein-Tank (with Emerald Axe or TA) because back then, magic tanks didn't really exist yet. Do it right and you can tank any Rein with 0 damage, so four of them is no big deal anymore.

These days, theres a decent amount of units and skills to pick from to make Reinhardt cry, so it's way less effective than it was, and definitely less useful than making a well-rounded team using all colors available. The red Rein brings some coverage in, so that's an improvement, gotta wait for a green Reinhardt though to make full Rein teams completely viable. I can put Surtr in and he facetanks all Reins taking near-zero damage, including the red one.

I understand he is difficult if you don't have a dedicated counter for him. But these days, almost everyone has, because of how broken he was when he was first released. If you have trouble against him, I recommend upgrading a Titania or similar unit with feathers to deal with him.

No.

However, the closest I've seen is 2 Blue Reins, a Blue Olwen, and a Green Olwen stuck in a 2 by 2 box.

Aversa; that is all.

No, but i encountered this fuckfest.

I seen him in arena few times, it was horrible. (i mean blue tome one, if that would be WT Rein i would win those matches).
I'm fine with him in AA and AR tho, my Ursula is ready to kill him.