I have not been checking the transfer news therefore do not know about the latest rumours. Son is a legend at Tottenham, if he is sold before the season begins it will immediately put him against the fans (and that is not a good way to start).
They're getting Mbeumo - that's Frank priority signing right now, they worked well together at Brentford but I'm more worried about them losing Son; he was supposed to meet with the new manager to know he's fate. I haven't been following up transfer market, I'm more focused on CWC tournament fantasy at the moment 
He's fans favourite, I read some comments from Totteham fan pages and not a single person wants him to be sold, not after his loyalty and captaining the team to Europa league glory. He's not getting younger and the pace is not longer there but his leadership and experience is important to whatever project Frank wants to build.
Did you watch Delap in our last match? Looking like huge upgrade on Jackson tbh.