The zf8 has issues, it benefits from frequent changes but it is a damn yarn of a fluid change, as in it is a process and even when complete it is a two video process just to check the level. Furthermore, it doesn't like high quality fluids that may extend the interval a bit. And then there is this, the zf8 fluid which was supposed to be higher quality is nothing more then a maxlife type fluid with a different color, it's all on the stat sheet. It is a risk to use a high quality fluids in the zf8, the risk is they tend to be too slippery for this application. It only works some of the time wouldn't move the needle for me when considering what fluid to use. The safe moves, maxlife multi vehicle (different color though) , zf8 lifegard, or OEM. learn to embrace the suck and use maxlife and change it often, like under 50k miles would be my thought on it. it could be worse, some fords you need to drop the trans just to change the fluid, no joke.
I would use Amsoil in diffs and t case.
