Good post hilts and I understand exactly the line of thinking you're taking. From what I can tell you're mindset is a conservative / balanced approach but Pep is going for full on all out attack. I couldn't agree with you more about Mendy pulling a hammy and toure and dinho as the DM. I'm also not comfortable with stones. I would counter with this..I've always thought this was a 5-7 year project so it was never going to be complete this window. I also think he's telling all these youngsters Sane, Bernardo, Jesus, mendy, and Mbappe that he's fully committed to the long term and that we're sorting the attack out this window for good. DM + CB will be next summer with a true LB as cover as well. We just can't finish it all this window. It's gotta be one more.
I think for Mbappe you just have to pass on the backup LB + a VVD type in that particular window and look at the long term and I'm positive that's what we're doing. Next summer is when we get the DM and probably that VVD type.
And yes, we will have an unhappy Raz (or sane )or Midfielder or whomever but tough titty said the kitty. So be it.