It is understood that the United players would welcome assistant manager Ryan Giggs despite the Welshman's lack of experience and he is the preferred choice of both Ferguson and Charlton.
Former team-mates have said that Giggs quiet touchline demeanour and laidback public style do not give the whole story and point to the years he has spent gaining the knowledge that would allow him to take on one of the highest profile hotseats in management.
The most decorated player in the club's history, Giggs knows the club and its traditions better than anyone, giving him a 'triple tick' for that aspect of the job.
Giggs thinks he is capable and, if Van Gaal were to leave, he would be interested.
But could we afford to appoint someone with four games worth of experience and - if not- what happens then?
There are significant doubts about Giggs wanting to work with Mourinho, or indeed Mourinho wanting to work with him.
Tottenham manager Mauricio Pochettino has been touted as a potential replacement, along with Atletico boss Diego Simeone, Ronald Koeman and PSG manager Blanc - but none of them know the club like Giggs.
The lack of clarity at Old Trafford comes as most of United's rivals know exactly where they are heading.
Jurgen Klopp is relatively new to Liverpool, Pep Guardiola is on his way to City and Antonio Conte will join Chelsea after Euro 2016.
In announcing the Italian as their manager in April, Chelsea director Marina Granovskaia said they were pleased to have got the contract signed before the summer to aid the club's future planning.
If United are unable to announce who will be manager next season, it could prove costly in terms of player recruitment, especially if no decision is made until after the FA Cup final on May 21.
The impact of inconsistent results has not only led to managerial uncertainty.
Wayne Rooney's testimonial against Everton is scheduled for the 3 August but that clashes with the third qualifying round of the Europa League.
Should United finish fifth and fail to win the FA Cup we will almost certainly be playing in it.
The Reds pre-season plans would also be affected with the high profile Manchester derby fixture - in China on 25 July - is only three days out from the first leg of that Europa qualifier.