Both of the flicks are being shot in Romania by Don E. FauntLeRoy, the cinematographer turned director who has no less than three Steven Seagal movies under his belt. (So I'm guessing a pair of Anaconda sequels would actually be considered a promotion for Don.) And it looks like the producers are sticking to the old "search through a snake-infested jungle in search of something valuable" schpiel
The original Anaconda (1997) starred Jon Voight, Jennifer Lopez, Ice Cube, Eric Stoltz, Owen Wilson, Danny Trejo and Kari Wuhrer. The 2004 sequel -- Anacondas: The Hunt for the Blood Orchid -- starred Johnny Messner, Morris Chestnut, KaDee Strickland and Matthew Marsden. So if Anaconda 3 and 4 star David Hasselhoff and John Rhys-Davies, then I'm guessing Anaconda 5: Big Snake Babies will star someone like Andy Dick and Skeet Ulrich.
Having said all that, I'll rent anything with giant animals and screaming victims. Monster flicks are my true Kryptonite.