What do you think about swapping the Lascannon out, adding a Melta to the jump squad and giving that sergeant melta bombs? This will mean they are definitely ghosting the Razorbacks on their approach, but changes their role to accommodate a bit of armour punch. Figure if I'm close enough to hit it with a MG I'm close enough to charge as a backup if I miss shooting. I know I lose the one S9 shot, but I gain Melta and maintain a S8 shot from the same model.
The hand flamers are a crucial aspect of defence against charging, plus those squads working in conjunction dropping 4 templates on an objective should be enough to get the dice rolling and hopefully in my favour. This is the tactic based around that thought.
Coincidentally, this list requires much less painting and not having to do constant special weapons will speed the process. I've already got a missile launcher dude painted, but no lascannon guy.
As a side note, when firing an emplaced weapon does the rest of the squad have to shoot at the same target?