Go for it. You have 3 rangers that work with Green, Red, Violet/Pink. I do think blue still works for Billy as he was the hope of the team as he could repair a lot of the equipment, I think Indigo might work better for Zack since he brought his dance style and culture into his techniques and the Indigo tribe seems more steeped in tradition than most, Yellow might still work for Trini as she was a fierce fighter and I do think a sabertooth tiger would intimidate anyone. Now here's an idea for a second season in one of the comics for DC they have one representative of each lantern core unite all the beams of the factions to form the white light that the white lanterns use (representing life in the spectrum). Now we know that Tommy becomes the White Ranger in the second season of MMPR. So what if Lord Zed actually had the Black Ring of Death (which is why the lanterns needed the white light to begin with) . Lord Zed finds a way to destroy Tommy's power battery leaving the ring with a limited charge, yet Zordon knows of a prophecy that if the rings unite their powers a new lantern would be made so Tommy uses the last of his powers and combines it with the others and in return gets the new white lantern that turns his ring white.