Did you try Scala?
As far as I know, Scala is ARexx addressable and supports a wide range of ANIM opt codes and display modes ... and Scala does handle interlaced EHB with fulll overscan.
I'm not sure if Scala plays ANIM-8 files as well, I didn't have such files to test that. But maybe you consider using Scala's AnimLab, a utility program to convert anims in Scala's own 32bit anim format (which it plays pretty fast).
