Cut in La Sportiva G5 Evo

1. Does the yellow part give any extra waterproofing and/or support?

2. What is the best way to fix this? My thought was super glue and hold it down. 

Super glue might be too brittle, might try seamgrip.

You can try filling with a waterproof sealant and then applying the appropriate repair patch.

Gear aid has the right products and solutions, like Aquaseal/Seam Grip W/Tenacious Tape Repair Tape 

Do nothing or a dab of seam grip or shoe goo. I don't think a repair patch will be last very long in the application and agree that super glue is too brittle. 

The damage likely doesn't compromise the gortex membrane although the yellow band is probably providing some benefits in terms of waterproofing as a first line of defence before the membrane. 

You might wash the area to help the Seam Grip stick better. It is the toughest of the materials mentioned and maybe best for the location.

Washing is mandatory, you might also look into the patches thermarest uses, I've had good luck with those on weird repairs.