My Question : Do I treat the platoon move as one entity - which will place just ONE PDF - Either against the 2/1 squad or the HMG - or do BOTH enemy occupied cards come under fire?
One PDF. This is made (fairly) clear in 6.2.3.
I think just one card is targeted - following the protocol outlined in 6.1.1 - which, in this example, will mean that the HMG will be my target as this projects the highest VOF. Correct?
I'm believe this is correct, even though the wording in 6.1.1 in that case is a bit unfortunate. In other rules sections they speak about "best VOF" which would have been preferable if they mean to target the most dangerous enemy.