Here we go, I'm making a detailed flow chart on grab follow-ups for Luigi.
1. Pummel once or twice, d-throw. If hits tech, go to 4, if misses tech, go to 2
2. Up-smash (may require pivot) if it will kill, If not go to 3
3. Up-tilt (may require pivot)
4. Tech roll go to 4, tech in place go to 6
4. At or above kill percent for up-smash, up-smash. If below, find 5
5. Running d-tilt, then try to snag their landing with any of your tools really
6. Re-grab on reaction to this
Now Samus.
1. Pummel once or twice, d-throw, missed tech go to 2. Tech go to 4
2. Up-smash (again, may need a pivot) if they are above kill percent. If not go to 3
3. Up-tilt, (may require pivot)
4. Reaction re-grabs until 5 will kill, or they intentionally miss tech.
5. Waveshine up-smash