I can't see Sabu or Taz lasting long in the WWF at all. Sabu didn't talk so at best, he has a 1995 Hakushi factor going for him and even then, he would have been too ahead of his time. There's no "light heavyweight" division to make him a focal point star in, he can't talk and the managers by 1995/1996 were pretty limited in the WWF, and he doesn't look like a WWF superstar. I think he probably could've made it 6-8 months then bounced by doing something to get himself fired.
Taz would have had no chance. His promos worked in ECW because he could be basically unfiltered. No way WWF lets him do that. He was super short for even the 1995 era and I think if he came in during 1996, at best he probably ends up part of the Nation of Domination in the D-Lo type background role. Best case scenario, Taz makes it as a "Sparkplugg Holly" type low card talent who sticks around for 2 years then leaves. Think your Chris Candidos as Bodydonna Skip type stuff.
People forget that while the matches could've been good... you have to think the WWF style at that time. They may've had guys like Bret and Shawn and Foley in 1996/1997 but #1: Those guys were all legitimately big size-wise. Shawn and Bret were both around 6'0" too IIRC and they were considered "small" in that era, #2: Those guys had crazy charisma and even Bret could cut decent enough promos to build up a match for a PPV, #3: It took Foley 2-3 years to really build himself as a credible WWF Main Eventer and it took doing feuds & angles with Undertaker, Vince, Austin, heel Triple H in late '99/early '00, and The Rock, etc. How many talents would get that many opportunities? And that's with Foley being one of the best mic men of the 1990s.