The two moves will end up costing the club in the region of £18 million, per The Sun.
Diakhaby will cost £8 million, while Limbombe is valued at £10 million by his club.
22-year-old Diakhaby is expected to be present at Huddersfield by the end of the week to undergo his medical.
Limbombe, 24, should follow soon after.
Both players are eager to get regular playing time at Huddersfield after an indifferent past season, where they were used sparingly at their clubs.