Manchester United intend to plough ahead with their transfer business during the potentially long process of waiting for a new manager to start – almost three months in Louis van Gaal's case – and their extensive inquiries include exploring the possibility of whether Paris Saint-Germain might sell Edinson Cavani.

United confidently expect to close a deal of around £30m for Luke Shaw, offering the teenage Southampton full-back a lucrative financial package that could be worth as much as £100,000-a-week over five years. The offer will be difficult for Chelsea to match bearing in mind their issues over keeping in line with Uefa's financial fair play rules. Ed Woodward, United's chief executive, has been made aware that Cavani might be available and is also tempted to look again at Cesc Fábregas's position at Barcelona, despite the unsatisfactory way it turned out when they tried to sign him last summer.

Although United were accused of handling the process badly at the time, the club remain convinced that Fábregas was keen to join them only for the proposed move to break down because of the politics and sensitivities that surround his association with Barcelona. Their interest is sustained in part because Robin van Persie, Fábregas's close friend, has reported that the former Arsenal midfielder wanted the move to happen, using the striker as an intermediary, and Woodward was told exactly the same by the relevant agents.

United failed with bids of £25m and £30m, as well as making a verbal offer in the region of £35m, and could not persuade Fábregas to go public or try to force the issue. This time they will approach it more cautiously but, again, with the sense that both Fábregas and Barcelona are more open to the idea than their public utterances might lead people to suspect.

What is increasingly clear is that United realise they will have to spend significant sums of money if one of Van Gaal or Carlo Ancelotti, the two managers uppermost in their thoughts, is to repair the damage that was caused in the David Moyes era. The team, who are out of next season's Champions League, lie seventh in the Premier League, 23 points off the top, and are about to be deposed as champions.

Woodward is confident that two deals have already provisionally been put in place, though those names have not been revealed. Their interest is known in several high-calibre players such as Marco Reus and Ilkay Gundogan at Borussia Dortmund, Toni Kroos at Bayern Munich and Sporting Lisbon's William Carvalho.

Chelsea were considered favourites to land Shaw, a lifelong Chelsea supporter whose parents live near the club's Cobham training centre in Surrey. Yet the terms plus the lure of becoming Patrice Evra's instant successor at left-back have boosted confidence at Old Trafford that the 18-year-old England prospect will join, becoming the highest paid teenager in English football.

The priority for United is in midfield, as well as finding replacements for the departing Nemanja Vidic and Rio Ferdinand, but United have already held preliminary talks to ascertain whether Cavani might be prised away from PSG. The fee would be high, potentially £60m for a 27-year-old, in complete contrast to the policy that existed at Old Trafford a few years ago whereby the club simply would not countenance, post-Dimitar Berbatov, paying huge amounts for a player of that age.

Cavani signed from Napoli for £52.7m last summer, making him the sixth most expensive player in the world. His introduction to Ligue 1 was hugely impressive at first but the Uruguayan's form has diminished in the second part of the season and he was unable to exert any real influence in either leg of the Champions League quarter-final against Chelsea.

Although United are not short of forwards, the reason for their interest is two-fold. First, there is a recognition at Old Trafford that the team have lacked dynamism and need an injection of directness and pace in attack. Second, Woodward wants to bring a superstar to the club and his ambition of bringing Cristiano Ronaldo back to Manchester seems a long way away.

Whoever takes over from Ryan Giggs – who will hold his first press conference as interim manager on Friday – will be involved in the process as soon as it becomes possible. In Ancelotti's case, the earliest that could happen would be the end of May. However, United have to establish the chance of him leaving Real Madrid and a lot depends on how his team finish the season.

For Van Gaal, it would be even longer, as he prepares to take Holland to the World Cup finals. United, deliberating between the two, intend to make their first approaches in the next two weeks.

The debate over Adnan Januzaj's international future appears to have been settled after the Belgium coach, Marc Wilmots, took to Twitter to announce the teenager has committed himself to the land of his birth. The 19-year-old – who was born in Brussels to Kosovar-Albanian parents – is eligible to play for up to five countries, with Turkey and England also believed to have registered an interest. However, with Belgium preparing to take part in their first World Cup finals since 2002, Wilmost has confirmed that Januzaj will be avaialble for selection in Brazil.