It's unlikely that either Feinstein or McConnell will be reelected, regardless of when the election is held. The scale of their health effects weren't known at their last election.
Compared to paying enough attention to all of our myriad elected officials, to know which ones of them are up to what kinds of crooked dealings...having to vote on a Tuesday is a "...and remember to staple your 47-part filled-out-by-hand paper tax filing in the upper-left corner before mailing it to the IRS" sort of detail.