Wafula (23), who played under Craig Elliott at Shaw Lane last season, has linked up with the Pilgrims after spending the first half of the campaign with Vanarama National League North neighbours Gainsborough Trinity.
Wafula (pictured) began his career at Chesterfield and has also represented Worksop Town.
Dyche (20), meanwhile, has joined the Pilgrims on an initial month-long youth loan deal from Scunthorpe United.
He has previous loan experience of National League North with Bradford Park Avenue and netted 18 goals in 38 appearances during two loan spells with Ashton United at the end of last season and the start of the current campaign.
Both players are eligible to make their United debuts against Curzon Ashton on Saturday afternoon.
PIC: John Rudkin.