I'm not sure I understand exactly what you're trying to achieve...
Hello,
I have xprv key from mycelium wallet exported. I am trying to recreate my 12 word seed. Is this possible?
You want to recreate the 12 word seed from the private key? If so, no that's not possible.
If not, is it possible to import this somehow in mycelium? Why did they make this thing so hard?
You can't import a private key, but you can sweep it (move the funds from the address associated with that PR to one of your Mycelium addresses).
Go to the menu = Cold storage, and then Clipboard (if you have it copied) or QR if you have it printed.
I am trying to obtain a private key of 1 ETH address?
What do you mean? Mycelium is a BTC address.