You've got me confused but use ST141 steering arms. I'm pretty sure the AE86 steering arms compatible with anything else.
Yeah should be fine using XT130 LCA's on ST141 struts. Put it this way, I've read about people using XT130 struts on KE70 LCA's and others using ST141 struts on the KE70 LCA's as well. If they both fit a common thing, then they must be the same?
Sprinter, I think was the shortest arm available. KE70 wasn't much longer but different bolt spacing.
Look at
GX60, ST141, RA65, KE70 (opposite side).
How does the AE86 compare to that?
RCA's, I guess so, will have to be custom made.