The speculation along those lines has been around for months. The specific contention combined with July 4 is new yesterday, and seems to come from Rob Schumacher/The Republic.
In that article, VOX is cited for a non-controversial proposition about timing of resignation and mechanism to name replacement.
The WaPo article is part of that month or months long general speculation about who might be named to replace John McCain.
I’ve seen the speculation before, but without something solid I don’t want to get bent out of shape yet. What kind of outfit is The Republic? Trustworthy at all? I can’t dig around, must pry away from computer shortly. Like an hour ago...