Will it ever be back to download?

Probably not. You should cut your losses now

The ban is not lifted trump just made it so the app is online and usable if you have it. However the ban is still technically in place which means if Google or Apple put it for download in store they would technically be breaking the law and the court order and could be sued. Trump has to officially change the court order and he has stated that will only happen at a later date and only if Tiktok becomes 50% owned by the USA. Pretty sure him or Elon will try to buy that 50% of tiktok then once that happens he will say that it is no longer a security threat since it is half owned by the USA and there is now no longer a need for the ban and court order to still be in effect. But until then I can't see it being back in the store to download because it opens up the app store owners to being sued for providing a download for it while on paper it's still banned.

We don’t know.

Get Nord vpn to change your location. See if that works 

Hard to say right now

Find an alternative app store thats not Google or Apple.Search for tiktok on a secondary search engine like duck duck go.

Hopefully not

it should after trump officially signs the 90 days

I deleted thinking it updated on the 18

Just download the apk, install, restart your phone and login.

Edit: only for android phone users only

Edit2: if this doesn’t work then try using hotspot that has vpn and use canada. Repeat the first one I’ve said and connect to hotspot that has VPN located on canada.