My understanding is that many lines of orange hypo are compatible with each other, though not all. I know for a fact that Bell Orange hypos are compatible with NERD Orange hypos because I've produced orange hypos from a Bell line orange hypo male bred to a NERD het orange hypo female. I've seen many CH orange hypos available for sale over the years, and there is no way to know if they are compatible with the more established lines until the breeding is done, so it's good to inquire about the breeding lines when purchasing since I think there are potentially many lines (oranges and others) out there now.
I'd read in the past that some green hypo lines are compatible with orange hypos. I have a hypo male that was produced by Jay Nelson (Chico Reptiles) from a green hypo male and a het orange hypo female (female originally from EBN). Unfortunately not all green lines are compatible with the orange ones so determining compatibility is a matter of trial and error, or staying within the same or proven lines.
Hope this helps.
P.S. I'll try to post pics of some orange hypos later for you. I know what you mean about seeing people post "orange" hypos that don't look very orange. Like any morph, there are variations in color, and some that I've seen do seem to have a greenish or yellowish hue. Perhaps that is due to green or yellow hypo having been mixed into the breeding in its ancestry, or perhaps that is part of the normal variation in color expression.