This I think you call it small hacksawNo, I wouldn't worry about that other part.
How did you get such nice clean straight cuts?
What tool did you use?
How did you do your measurements?
How do you plan to cover it?
Personally, (despite dropping a few tanks) I think the cut-out is a GREAT idea.
These pumps often go without warning... but they ALL eventually go!
I put the cutouts back,have made a frame and sealed it so I take it in emergency situation-I live in Sweden and it’s cold and remote sometimes and I want a spare one with me if I camp I the mountainsLooks like a fuel tank vent valve, but I could be wrong. Either way I would want access to it. Make the hole a little larger. I have not done that mod to any of my vans. I have a lift so I just drop the tank. If I was in the outback I probably wouldn’t have a pump with me. What are going to make the door out of?