If i run 2 bots per proxy, one in daytime the other one in nighttime and one of them gets perma banned, will the other one get chainbanned OR does this only apply for home ips?

I think no one knows for sure, but in my experience when they are not botting at the same time and they have not interacted with each other they wont get chainbanned.

But if I was you, if you care about the accounts just buy another proxy just to play it safe  

I've yet to experience a chain ban because I've used to same proxy IP at different times (or concurrently) but that being said I also don't know if any of the bot I've had have been banned faster because of the IPs being banned / flagged so it's all anecdotal really. No proof either way.

Safest bet is to use a unique proxy IP for each bot.

I mean it’s a yes and no. Tbh you never can be 100% sure. I’ve had accounts share proxies botting at the same time, even doing the same things. Sometimes one account will get banned the others will be fine. Sometimes they will all get wiped and I can only suspect a chain ban, but keyword, suspect. 

You can’t be sure if it’s a genuine chain ban, but it’s safe practice to limit accounts per proxy