I am Ex Plat on AA and tend to fly mostly on OW partners. Due to the problems with Swiss Air, my trip to VIE in November has now been rerouted through FRA and down to VIE on LH. I currently have zero miles or status with any star partners. I figure I can do one of the following for the FRA to VIE leg:

1)Sign up for UA miles.
2)Sign up for LH miles.
3)Sign up for another star airline miles.
4)None of the above.

Any advice you can provide would he helpful.

Thank you in advance for your help.