Geri Halliwell-Horner picked up an honorary doctorate because of her work as an author and singer.
Miss Saigon has "hurt and angered" many southeast Asian viewers, the New Earth company says.
The former Hear'Say singer hopes to return the following week with her partner Graziano di Prima.
The former Beatles drummer is selling life-size statues of his signature hand gesture.
The move comes after several countries had their votes cancelled at this year's contest.
An average audience of 9.4 million watched the Wales match, while 7.8 million watched England.
Staff at a Manchester bookshop thought it was a "hoax" when they were told the U2 singer would visit.
The guitarist and singer was a key member of Cuba's Nuevo Trova movement after the revolution.
The arts festival says 18m people across the UK have enjoyed Unboxed's programme of events.
Last month, a US court blocked the planned deal, saying it could "substantially" weaken competition.