Both of these projects are circa 1991 and neither film got made. HUMANOIDS FROM THE DEEP 2 carried the subtitle THE NEXT GENERATION. Note producer Ovidio Assonitis' pseudonym Oliver Hellman (clever) slated to direct PIRANHA 3. Interestingly, Roger Corman did produce remakes of both films in 1995-6 for Showtime. A second remake of PIRANHA is forthcoming. Ugh.
#2 - HUMANOIDS FROM THE DEEP 2
#3 - PIRANHA 3