Alot of Combat Engineers are just Construction Workers with 6 weeks basic training. We are talking about highly training construction engineers will basic weapon skills to survival in a battlefield environmental.
Most of the time, these guys working in the rear of the main force to rebuild bridge and help the rear guard and other support unit get forward.
If they are need in the front line they have full combat troop assigned to help them protected them. The tactical skill they need with be rigging rock falls to trap armoured units or other slowing methods and to me Tactics is not right for this, Surveyor is possibly closer.
At the end of the day Combat Engineers are a high specialised non combat unit, trained to survival the modern battlefield and to work with Full Combat troop support. Medical staff are trained to fight and use weapon, but hardly any will fire them. I think Engineers will be the same, the weapons of choice will be ones that reshape and the lands and make things hard for the enemy.