The developments sparked panic among supporters, with United yet to return to the table after Brentford rejected an opening bid worth £45million plus £10m in add-ons.
But fresh reports have simmered the uproar. Sky Germany state that Frank will attempt to lure Mbeumo to North London after replacing Ange Postecoglou in the hot seat.
That said, Mbeumo is said to have already given his approval to a United transfer, going as far as reaching a verbal agreement over his contract in Manchester.
It's claimed that the M16 giants remain confident a deal will eventually go through to add the Cameroon international to Matheus Cunha in Amorim's attack.
United confirmed the signing of Cunha on Thursday, recruiting the 26-year-old in a £62.5m deal from Wolves after a stellar campaign.
Amorim also reportedly wants a striker after Mbeumo. However, a swoop for Viktor Gyokeres appears off the table after the Sporting star rejected a reunion.
Napoli's Victor Osimhen, Jean-Philippe Mateta of Crystal Palace and Eintracht Frankfurt man Hugo Ekitike are among the alternatives linked.
United's early focus on bolstering their attacking firepower comes as no surprise after totalling just 44 goals in the Premier League last season.
Mbeumo and Cunha scored a combined 35 alone. The Red Devils' joint top-scorers, Bruno Fernandes and Amad, managed just eight each.
Rasmus Hojlund scored just four times in the Premier League, while Joshua Zirkzee only notched three after his £36.5m move from Bologna.
United reportedly also want their business to extend beyond the attack, but they require player sales to generate funds due to the cost of no European football next season.
Amorim is keen on a new goalkeeper and midfielder, but there is little chance of him adding those players before offloading the likes of Alejandro Garnacho, Marcus Rashford and Antony.