DEN-FRA and FRA-... on 4-3 is zeroed out on the lufthansa website.

Based on that I was able to make a parallel reservation on United metal at least to FRA. (Which is not my original destination but better than nothing). Friendly lady at the 1K line claimed these seats are kept on hold for me and my family until either the LH flight is officially canceled, or I am confirmed on LH (if for whatever reason the situation changes)

Yay! I will be able to start my vacation (almost) on time!