I think it's plausible that LB will stay as it is. Young is offensively much better than Valencia, he has also been super reliable in terms of injuries last season. Shaw will be the one to play meaningless Cup games or games against lower placed teams in between CL matches.
Neither of Young or Valencia will be sold, those two are senior figures in the squad and fit Mourinho's definition of soldiers on the pitch.
Shaw won't be sold because he sits on a big contract and he has no problems earning his paychecks for 1 game a month. If you add another Fullback, that would be 5 players, which is really unnecessary. FB is not a position like CM or AM where you rotate often. Especially if you have two players who can be used on both sides (Young and Dalot).
The funds could be used elsewhere and a CB is clearly the next in line in terms of priorities. I think Mourinho is fed up with Bailly and Jones, Rojo is seen as a back up and Smalling as the only reliable starter. I don't think a Lindelof loan is out of the realms of possibility. In that case, a ball playing CB comes in to take the starting spot next to Smalling.
Out of the ones mentioned in the MEN article, only Gimenez and Soyuncu would be cheaper than Alderweireld. I can see Utd going for Soyuncu now that Sokratis is at Arsenal. Freiburg wants 35m Euros for him and that fits the budget easily.
I don't understand the thing with the CF backup at all, especially if Martial is staying. Arnautovic is clearly the front runner for that since Mandzukic declared he would stay after Allegri confirmed to be at Juve next season. The Austrian, however, would cost 50m and thats not enough to compete with Lukaku or Sanchez for starting positions, but way too much for a backup striker.
The lucky case for Utd would be Bale becoming available and them channeling all the funds into that one to fix the RW position. Don't see it happen, now that Zidane is not there anymore. Bale loves it at Madrid and doesn't want to be pushed out.
That there is no chase after RW players like Mahrez or Pulisic is mind-boggling for me, the position with zero players in the squad is clearly the weakest, not the one with 5 internationals
Seems to me like Mourinho has lost his mojo in squad building and hasn't got a clue about what to do with the squad to bring it to the next level.
Signing one CB and not addressing the hole at RW for the 3rd summer straight is a clear sign of desperation.