[Welpe]

You didn't specify a ruleset so I'll assume Federation.

If you judge that the quarterback committed intentional grounding, you would have a safety since the penalty is enforced from the spot of the foul and the foul occurred in the endzone.

Now if the lineman (or any ineligible receiver) intentionally touches the pass, they have committed illegal touching. Illegal touching is enforced using the all but one principle. Since this is a loose ball play, the basic spot is the previous spot. If the touching occurred beyond the basic spot, the penalty is enforced from the basic spot. If the penalty occurred behind the basic spot, the penalty is enforced from the spot of the foul. Illegal touching would only be a safety if it occurred in the endzone.

If the lineman did not intentionally touch the pass, say it hit him in the back, you would have no foul for illegal touching.

In conclusion, your possible penalty scenarios are.

a) Intentional grounding by the QB, legal touching by the lineman. If penalty is accepted, it is a safety.

b) Intentional grounding by the QB, illegal touching by the lineman. If the IG penalty is accepted, it will be a safety. If the illegal touching is accepted, it will be enforced via the all but one principle that I outlined above.

c) No intentional grounding, legal touching. No fouls. Result of the play.