I have a feeling that if they go ahead and do this FH remake idea, it will be a flop. I doubt they would keep it similar enough to the FH tv show to appeal to a lot of fans of FH. I think there's a good chance the sets would be completely different and that it would be set in the present rather than during the time of its original run. It would have more appeal if they set it in the late 80s, made the house look the same, and had the characters wear old clothes from the late 80s. That might work for me with actors able to look and feel enough like the original cast and characters.
The other problem they have with the cast is getting the ages right. For instance, it won't work if they have a 1 year old Michelle with an 11 year old Stephanie and a 17 year old DJ, because the age difference isn't right. I figure they would mess this up a bit.
A FH movie with the original actors would probably also be a flop. At this point it would simply be too difficult to get a good balance between keeping the movie similar enough to the TV show, and not having all the characters look like their lives have been going nowhere since the end of FH on tv.