I brew year round, but then I'm a bit of an odd one I think as I basically brew what suits the season, kinda like our ancestors probably did I suppose. The most temp control I have ever used was a heat mat taped to the side of an FV, and blankets wrapped around.
Probably why I'm enjoying Kveik so much, it lets you brew beer without having to pamper it. If you read the blogs about Norwegian farmers, they're not building fermentation fridges etc, they're cooling their wort to about 40 degrees or whatever, then wrapping it up nice and cosy to keep the heat in, then in goes the yeast. The yeast itself produces heat, keeping the temps up as the insulation keeps that heat in the wort. Then when the yeast has done it's job, the wort cools down naturally. I even brewed during that summer scorcher, made for a stunner of a Belgian Wit.... The sweat was pouring off me I can tell you..... But when you have a yeast that likes the warm, hot weather is a boon!
From my reading around, Omega Hothead Ale has become really popular in the US thanks to the whole not needing temp control in warm weather aspect..
As to yeast mutating, sounds more like adaptation, with some of the strains thriving more than others in the conditions you are using it in, rather than mutation, giving you different results. Or it could just be the old neighbouring farms using different Kveik...
Brewers droop - dry hopping is fine from what I've read re Ebbegarden, it's just boil hops that can cause problems, flame out and dry hop ones are supposed to be fine. From my research, this makes it a brilliant yeast for beers like NEIPA, where folks are putting the hops in later anyway. Not used mine yet though, it's still in it's phial in the fridge. I'll do what I always do though, and do a big starter with it first, then take about 5-10mls (that's usually all you need) out to use in a brew, store the rest for future use. Check your source though, in case you have the same stuff David is brewing with. Most of the Ebbegarden I've seen folks using though is the same stuff Lars Garshol collected, which gives nice tropical fruit flavours, and enhances hop bitterness. Not all of the Norwegian farmers in a particular region though actually have the same yeast, some have mixed it at some point, others have replaced it completely using a Kveik for a neighbouring region after theirs got contaminated with something less than pleasant... Any time spent researching the topic, you'll find plenty of accounts of this occurring, and the so called Kveik registry is full of records of different Kveiks from neighbouring farms that are either totally different, then ones from different regions that are actually so similar as to suggest that at some point a Kveik got shared from one region to another. This isn't lab yeast, nothing is black and white. Just browsing through this thread, you'll find a discussion about somebody who bought a yeast that was sold as Kveik, which is actually a strain of Candida (so not Kveik), but it's on the farmhouse yeast registry (pretty sure that used to be called the Kveik registry) (with a note that it's not Kveik) because it was one of the yeasts (there are wild yeasts on there too, also not Kveik) Lars Garshol was given by a Norwegian farm on his travels.
They can't even make their mind up on how to name the yeasts.... Flipping from naming them after the farmer they got them from, to the region they're from... Perfect example, Stranda. Stranda obviously comes from Stranda (Omega Hothead Ale is Stranda), but so does Hovden (named after the guy it came from), which may or may not actually just be Stranda anyway....
Personally, I'd say your best bet if you want to experiment with Kveik is to do just that, experiment. Get as many strains, from as many sources, as you can. Use the farmhouse yeast registry as your baseline, remember to under-pitch (compared to lab yeast), and go for it. Over time you will find what you like, and what works best for what beer. Put it this way, I've so far made paler golden type ales and porters of varying shades with both Sigmund's Voss (Yeast Bay Isolate) and Omega Hothead Ale (Stranda single strain), and the porters are the nicer beers. But then, I prefer darker beers....
Don't go by what any of us say, as it's all just our opinion at the end of the day.