Question about Inquisitors leading units from other armies.

This is more out of curiosity honestly but:

All of the Inquisitors can lead "Imperium Battleline Units"

Many of the Space Marine Chapter specific models and a bunch of Legends units have rules that say "if a leader can be attached to unit x, it can be attached to this unit instead"

If "unit x" unit mentioned is a Battleline unit, can an Inquisitor lead the other unit even if its not battleline?

For Example:

Black Templar Sword Bretheren can be led by a unit that can normaly lead an Intercessor Squad.

An Intercessor Squad is an Imperial Battleline unit, so an Inquisitor can lead it.

Since an Inquisitor can lead and Intercessor Squad because they're Battleline, and even though Sword Brethren aren't battleline but can be led by anybody who can lead Intercessors, can an Inquisitor lead Sword Brethren?

Or does the Battleline requirement on the Inquisitor cancel out the Sword Brethren's ability?