WOW that is some Crusty Stuff. I have seen folks Soak the Crusty parts in Vinegar and let it work to remove Rust....
That Interconnect hose is really bad, going back you need to use Submersible Fuel Injection hose. I can imagine what the inside of the tank and filler neck look like as well.
I forgot to link the HOW do I change my in-tank pump out.
https://volkswagenownersclub.com/vw...1993-mk1-How-to-change-your-in-tank-fuel-pump
Yes that is the correct in-tank pump, and years ago, O'Reilly's in Mobile Ala wanted 120 bucks for it....(usually costs me 50...as I was 300 miles from home, I found a OLD Beetle shop that sold me one for 38...

)
Bare Joints submerged in fuel? Sure they are Bare... But you have to remember that your sending unit is a Rheostat, that is varying the resistance of ground to the Fuel gauge and at the same time is sending the +12, and Ground to the pump, and that it isn't shorting out. Vary tried and true method of these Critters.
Once you get the thing a little more cleaned, you can "Carefully as they can break" Pry the fingers off the cover, and remove it, be-warned you have a Finger wiper and Spring on the flat shaft so take good care to remove it as that spring can fly off.
I have a pair of end nipper wire cutters that are great for bending those tabs you just have to remember that older metal like that is
very brittle and rusty ones more prone to breakage...so take extreme care.
The Plastic on your Circuit Board may be very Brittle, so take Extreme Care in Trying to remove it....(READ BRITTLE PLASTIC DOESN'T Bend it BREAKS)
Using a 3 foot piece of String to hold the filter in place while you screw and Man-handle the thing back in prevents the Filter from falling off.
When you have it about ready to re-lock, just cut the string and pull on the Knotted side to remove.
PS: When using Photo-bucket, use the IMG link in a Thread, not the email or direct link, I have edited your post to reflect the change and display the photo instead of the link.
Imgur is nicer hosting site, and for them you use the "BB" link to have Photos Show up.