Yes... I think I took the view that the Decline Romans were less likely to field cats than the earlier list. Re the Eastern Roman list- certainly I can't recall any evidence for them in that period- certainly not in Belisarius' battles for instance. Earlier they had them, and later, but not at this time AFAIK.
Darts - probably short range I agree- although they had a longer range than javelins. I saw a video of a reenactor and they were scarily effective, thrown in a lob. I wouldn't want to encounter one!
Late Romans- I seem to be selling half of my army but hopefully will have recruited a new bigger one by next year. It'll all be on 20cm frontage, though, on my sexy wobbly-edged bases. A game would be fun! Would love to play at Chalgrove but bases may preclude.