I will ignore the United-Sneijder story because...Well because it's frighteningly frequent at coming up behind me and often biting me in the *rse the second I make a prediction.
Lassana story...I shall address
Real Madrid have a list of players they want (not have/will) to sell, that list includes Gago/Diarra for that I am 100 pct certain, Albiol/Higuain are more they ''will'' sell and Kaka is plausible if a big offer came in. If United put in a bid for Diarra of around 13-16 million euros it will probably get accepted, whether they will or not is up to United.
Juve had wanted Diarra to replace Melo who Conte wants rid of ASAP but they were put off by the price and actually are seriously keen on Vidal who imo they look to have tied up (somehow, would be perfect for MUFC).
Melo-United probably will not happen because of his temperament but the guy is a tank and at 10 million euros or less could be a steal, wondering if Arsenal would/could go back in for him...
At this minute I would say Lassana is more likely than Vidal, curve ball into the mix could be a United move for Ever Banega who has been told he can leave Valencia for 13 million euros and at an even bigger stretch if you fancy a real outside bet I would put some money down on Gargano/Annan.
Annan would be ideal but since Prem big boys let him go to Germany he's fell by the side a bit, would love him at United.