Whoever told you to lager a little longer was thinking of acetaldehyde, which appears as cidery or green apples flavor and is a intermediate compound in alcohol formation, so if present means the beer is too young.
But by your description I tend to think about contamination, specially by aceto...
Cold crash is a maturation step used to flocculate particles yielding cleaner beer.
Makes no sense clean your beer and then add some more particles into it.
To me cold crash is always the last step before bottling.
Yeasts ferments the best around 41c. If you ferment at this temp it would yield faster fermentation and higher attenuation, but lots of off flavors as well.
It is to avoid off flavors that you should control fermentation temps, not for increase fermentation.
Shane is correct about whirlpool hop addition rising ibu.
Another thing I can think about is that with that much of late hop additions, maybe you actually don’t have a high ibu, but all that aroma may be felt as bitterness, even that it is not.
For the batches you’ve already bottled, wait some...
Melanoidin mimics decoction, it’s not the same.
The difference will appear specially in light colored beers, like hefes or pilsners, where slight changes yields big changes in final beer.
You can use melanoidin, though, fits style very well.
Protein rest is just needed for grain bills with 25% plus of unmalted grains. Wheat may be malted or unmalted, have to see what kind are you using. In other cases, as said above, it yields thin, watery beer with poor head retention.
It does not reduces the amount of proteins, it breaks then into...
There's lots of mashes done this temp - 156.
It's just gonna yield a little high body and less abv.
No problems at all.
Maybe even the residual sugars of the higher mash temp are gonna leave some sweetness that is right on the style.
Sulphuric components are usually results from fermentation, but as it is very volatile, it tends to be taken out by the co2 that leaves the fermenter.
In fermentations that has a very low airlock (or blowoff or whatever) activity, or that are too vigorous for one day than finishes blowing off...