land contract question.

a land contract was created in 1984 with a seller and his wife to sell to buyer and buyers wife. in 85 the sellers wife died and the seller deeded the deceased wife portion to 3 other induvial. In 2010 the land contract was satisfied and the deed was transferred to said buyer. The new owner/buyer died in 2020 and his heirs are trying to sell the home. However the 3 induvial were never removed from the title even though the deed doesn't reflect the 3 indivuals only the deaceased. Only until the title search was done did the 3 names even show up. How do the heirs get the title free and clear to sell the home? How to remove the 3 names from the title?