All those missing lines can be ignored, they are all for the EGR which just pumps soot into the engine intake. I long ago removed all of it on all of ours....

As for the vacuum line connector you showed, that is very cracked, I'd look into replacing them to prevent leak related issues/malfunctions.

Go onto fastlane right here and buy a selection of crosses and y's for the vac system. No need to start ripping out the interior, but get to as many as you can under the hood, and then attack the ones under the carpet, etc. Youll also need some vac hose which can be had here.

Vacuum is so essential to so much of the car that you dont want leaks.

Find some vac plugs and properly plug up the vacuum system for the EGR (most everything that you see in the pictures you show. It looks like the lines are just open to the elements, which would be a huge vac leak and can effect shifting, shutdown, etc.

Personally Id replumb the EGR correctly and then plug the lines, or else get a proper cap-off kit as is sold by one of the members here, and do it right.

I love these cars and dont say this in a bad or mean way, but if vacuum hoses are your only problems, youve got it made... Its just that it is a 30 year old car.

Do post pictures and videos of anything you do, it would be great!

EGR stuff.

MB egr fun - YouTube

Just found another thing needing attention, my transmission dipstick is missing a part that potentially alters the height, leading to inaccurate readings. The fold down piece that locks it in place, so I'm looking for another one. Is this a suitable replacement? Have a ton of ebay bucks to redeem, figured this would be a good way to use them:
Mercedes R107 W123 W124 W126 R129 W140 W201 W202 W210 Transmission Dipstick NEW | eBay

Always a bit leery of buying what appears to ne non origional or universal parts, I'm particularly worried this may not be the same length as the one that's meant for the car

Id rather get one from a junkyard I think...

Im not sure that the lock does actually alter height, and if it does, it may be able to be compensated without doing a thing.