They could almost certainly become just "angel-blooded" and "devil-blooded." Even if aasimar and tiefling are fully open (they're not listed as forbidden in the OGL or anything), it might be better to de-D&D-ize them as much as possible.
FWIW, Heroforge instead of tiefling has "half-demon" and "infernal" (they both look like tieflings; "infernal" has wings) and "celestial".
Fiendfolk and angelfolk might be good. Or just have a species called "Outsider" and then they could have infernal, celestial, elemental, or other planar traits to choose from.