Ha, not a chance they'd be interested in him yet. Zero fear on that. Frankly, he still has a lot to prove but there are hopeful signs. This is his chance at a step up, as it was Pochettino's when he moved to Spurs.
Speaking of Pochettino, if they are actually replacing Mourinho they'd be daft not to look any further than him. He's taken that step up and he's ready for a Man Utd, Real Madrid, PSG type appointment.
Zidane would be a big roll of the dice for the PL and with their squad as it is now. It is certainly not presently full of galacticos as Real Madrid was. It's partly a rebuilding job and Pochettino would be the guy for that.
I know he's got his project going at Spurs, so they'd have to throw crazy money at him but make no mistake there is still a big step up from Spurs to Man United and that has to be tempting for him. There is currently a ceiling at Spurs in terms of financial backing, he likely wouldn't have those issues at Man United (at least to the same extent). I think they mentioned on the radio the other day Spurs's starting XI cost a little less than Pogba. That is the difference.