This movie was originally set to be a fresh reboot. Once Carl Ellsworth was added as a writer, it was decided that it would be made as a sequel to the original.
Zach Galligan said the movie is in the vein of Star Wars: Episode VII - The Force Awakens (2015) and might not ignore Gremlins 2.
During the filming of Gremlins 2 when Keye Luke (Mr Wing) realised that his character was to die in the movie he said "remember, in Gremlins 3, I'm a flashback".
Chris Columbus and Carl Ellsworth have been quoted saying, "the Gremlins should be puppets to appear more real," although Stephen Spielberg is known for using CGI to smooth out characters as needed.
It is unknown if the gremlins will be puppets, CGI creations or a combination of the two like Jurassic Park (1993).