Considering this, there is another option for this unit. One that maximizes their use. 10 veterans, 5 with combi-meltas ( for a unit that will probably just die most of the time and keeps the ammo optons flexible), 2 with lascannons, and then give the unit a drop pod for the combi meltas. This maximizes flexiblity, adds in long range firepower, with a short range punch that you will be sacrificing anyhow. I would also suggest a powerfist on the sergeant. This will give you some extra punch just encase you survive what will be counter punching you.
If anyone here reads this and uses this build for sternguard, or has other opinions on how to use this squad more efficiently, I would love to hear your comments.