if star crossed missed the 2nd target, did he return one or nome?

One — Star-Crossed still returns the target that's still legal.

Star-Crossed's "return a friendly unit and an enemy unit" is a single instruction with two targets, so Rule 359.3.e.8 applies: if fewer than all targets become invalid or unavailable, the instruction executes anyway, operating only on the targets that are still valid. FAQ #10821 confirms it doesn't fizzle.

The exception is if Star-Crossed itself gets countered (e.g., Repulse) — then nothing returns, because the whole spell is cleared from the chain rather than partially resolving (FAQ #12314).