I have no issues with the timetable. They planned to interview the younger assistants. Some will free up in 28 hours but not all of them. This could go on through right after the Super Bowl. Depends who's on the short list.
Loomis has 3 or 4 colleagues with GM experience helping him, so he's got the bases covered to do a search hearing from many prospects. They'll hear alot of plans and that's actually a good byproduct thing in the search, with the Saints' problems fairly complex, and needing multiple seasons to stop the bleeding and then potentially fix.
Had Loomis already hired McCarthy, to me that would've seemed like a lazy hire. They know what they can have in McCarthy, which is a baseline. They owe it to themselves to look at the OC head coach prospects because we've seen that profile succeed in the current game. That profile is younger and closer to the modern college game, which absolutely influences the NFL more now, making pocket statues like Carr more easily defended.