Been ages since I played anything DCS, but just purchased the F-86 and now have a X-55 HOTAS.
Can't seem to assign anything to the throttle quadrant (throttle axis, or otherwise).

Is there an issue, or am I just doing something stupid?

I don't have the F-86, but when I had my X-52 both throttle and stick were the same column.
Now with my X-55 I have a column for the stick and an other for the throttle

Hope it helps!

EDIT:

like that

EDIT2: I just discovered that you have to save 1 profile for the Throttle, and one for the stick.
spent 15 min to configure both and saved only 1 file(wich was the throttle) and the stick was empty

Yep, the lua profiles only save for the selected column. It's a good way to do it, but it's not intuitive and it took me a few tries before I discovered how it worked.

how do I use the ministick on the throttle to ''Slew''?

I created a profile with mouse x and mouse y as axis, and assigned those 4 new axis as the 4 button ingame that correspond to slew. It works within the program, but nothing happens ingame....

EDIT: also, is it possible that the mode button act as a button while to profile is active instead of switching between mode 1-2-3

Thank you very much Genbrien!