A couple of observations.
- ALL Dryer vents need maintenance and cleaning, the ones going up and out the roof need more. The total run by code is 14', elbows and flex pipe really slows down the flow.
- It looks like an addition was made and a roof was over framed on the original shingled roof. I would avoid cutting out any wall members below if you can.
- The micro exhaust vent pipe can be a 3x10 piece of ductwork to fit in a wall space and minimize structural remodel to the wall, turning to round pipe in the attic.
- New codes require venting for gas stoves, millions of homes don't meet code. Vent it if you can.
- Pull the insulation away from the Water Heater 'B' vent in the attic and as mentioned earlier, make sure that pipe is connected through the roof. Looks like weird retro above the water heater.
- Make sure you introduce outside combustion air to the water heater area if you frame it in.
- Have fun in the attic, looks cozy!