Questions about gloves, jacket, helmet

First season rider here and have accumulated some random questions.

1. I've got a pair of Five stunt evo 2 gloves (https://five-gloves.com/en/glove/stunt-evo2/). They're perforated and super light but riding at 10 degrees celsius, hands tend to get chilly fast (specially at the wrist) so I've been thinking of getting gauntlets for better protection and well warmth.

Since I don't have a lot of experience with gear just yet... am wondering what would be a good pick for 10 degrees but also maybe 25 degrees? Is there even an universal option -- e.g. should I get an air version of gauntlets (e.g. https://eu.alpinestars.com/products/sp-8-v3-air-gloves-black) or would you these thicker gauntlets feel just as cold because of the wind entering the perforated side.

I'm not sure what to expect since I can't test ride gloves before purchase.

2. I have a dainese textile jacket and any time i wear a sweatshirt under, the bottom seems to bend against my body and become under pressure and the zipper just tears open. That tells me, if i were to violently tumble, it would also open up -- not a lot of protection imo. Is this a not-supposed-to-wear-extra-clothes-under-stupid-situation or a faulty zipper?

3. Maybe i just have fat cheeks but when I ride I sometimes think about my cheeks pushed in between my teeth. I wouldn't say the helmet is too small tbh, it's a nice snug tight fit... but maybe too snug? Or is this normal and i'm just imagining shit. Also regardless on pinlock, my visor tends to fog up sometimes when idling. Like i said, it's humid here. Normal?

Thanks