Manchester United will give their new permanent manager the final decision on transfers, which means the club could face another traumatic summer in the market if their first choice, Louis van Gaal, is given the role.

The 62-year-old is hopeful that a deal to make him David Moyes' successor will be sealed this week, with the Holland coach keen to do so before starting his World Cup preparations on 7 May.

United are intent on avoiding a repeat of last year when Moyes and Ed Woodward, the executive vice-chairman, oversaw a disastrous window during which the pursuit of Cesc Fábregas, Leighton Baines, Ander Herrera and Fábio Coentrão ended in failure. Marouane Fellaini arrived from Everton on the closing day for £27.5m, £3.5m more than his buyout clause.

United are aiming for an overhaul of the squad. Yet even if Van Gaal was appointed in the next few days it would leave him almost no time to finalise targets before starting his World Cup buildup. As with most managers, his preference is to meet a player in person.

United believe they have done much work on the players who could arrive in the summer. However, this was done under Moyes' direction and Van Gaal is bound to have differing views.

Southampton's Luke Shaw, Toni Kroos of Bayern Munich and Paris Saint-Germain's Edinson Cavani are three players whom United believe they can sign. Although Van Gaal may also want them, he and the Dutch Football Association have stated that from Wednesday week his only focus will be Holland and the World Cup. How Woodward would deal with any complications encountered in the pursuit of targets – or any other player identified by Van Gaal – during this period is unclear.

It could mean deals having to wait until after Holland's World Cup campaign, which, if Van Gaal oversees a successful tournament, may not be until mid-July. Given the travails of last summer, this is recognised by the club as hardly ideal.

Although Van Gaal's advisers deny terms have been agreed, there is optimism that negotiations can be concluded and that an announcement can be made, even as soon as before the weekend.

If Van Gaal is appointed he could bring Patrick Kluivert as part of his coaching staff but the former Newcastle United striker would not be his No2. This would allow Van Gaal to offer the role to Ryan Giggs, the interim manager, although there would be no pressure from United to do so.

Giggs, who is in charge until the end of the season as player-manager, admits his future is yet to be decided. "I think that's another conversation as well. I don't know what I'm doing about playing, I don't know what's going to happen. It's something that I'll think about and decide with the appropriate people after the season."

The futures of many United players will remain in the balance until the next manager arrives. These include Patrice Evra and Rio Ferdinand but the captain, Nemanja Vidic, is definitely leaving.

Phil Jones believes he has learned much from Vidic. "It's just his all-round game," he said. "From his communication to his passing to his tackling to his heading, he's got so many great attributes. You learn off him every day in training, even if he doesn't say anything, you just watch and learn. He's been a huge influence on my career at United and has really helped me along the way. I owe him a lot and I am grateful for everything he's done."