The correct Bianchi X16 Agent Unlined Shoulder System for your Springfield Armory 1911 would be MPN:17252 (Right Hand), or MPN:17253 (Left Hand).
The Bianchi X16 Agent Unlined Shoulder System model # 17252 or model # 17253 should work for a Colt Commander.
Yes. The Bianchi X16 Agent Unlined Shoulder System offers a 4" option that fits barrels from 1.75"-4". MPN:17261
Our in-stock shoulder holsters for the Glock 30 are here: https://www.opticsplanet.com/holsters.html?_iv_availability=in-stock&_iv_gridSize=240&_iv_parent-gun-make=glock&_iv_parent-gun-model=glock-30&_iv_holster-type=shoulder-holster
The models that are open on the barrel end, should also work with the G21.
This model would work: 2VG-HT3-URCAH-UC-G2E-BK-COL
This holster is not available for the Hellcat, and the models Bianchi does have, do not accommodate the laser.
No, this holster will not work with the light/laser.
No. I do not see a compatible Bianchi shoulder holster for a Glock 30.
17259 is the appropriate model for that pistol.