A Shadowrun team is typically a group of specialists that are really good at the thing they do. If the team already have an Adept and a Magician then perhaps you should let them shine whenever the team stumbles upon a materialized spirit. Dealing with spirits is one of their high points. Let them do it.
Having said that, a more correct name for "Immunity to Normal Weapons" is probably "Resistance to Normal Weapons". As long as the spirit is not super powerful and as long as you bring a powerful enough weapon you can typically still put a serious dent in it. Weapons such as a monowhip, a 50" cal sniper rifle, an assault cannon, a high cal assault rifles (or battle rifle) loaded with explosive ammo, a vehicle mounted heavy machine gun, etc. And if everything else fails, bring out the really heavy artillery. Such as grenades and vehicle rockets.
The technomancer instead typically shine when it comes to things like;
- Matrix related legwork during the "lay of the land"-phase (matrix search, double checking intel, getting blueprints, patrol schedules etc).
- Matrix overwatch during the "social and/or physical infiltration"-phase (opening maglocks, controlling elevators, controlling sensors and turning off alarms, tracking enemy drones, snooping cameras, edit out team from live camera feeds).
- Matrix overwatch during the "exfile"-phase (opening doors, controlling elevators, delaying HTR, turning on sprinklers, turning off lights, creating diversions by activating unrelated alarms, messing with opponents vehicles during the car chase scene).