@Scooblitz I wouldn't consider scrapping based on a list like that.
Springs, as the others have said isn't a huge job and neither are the brake pipes. £500 labour sounds like main dealer prices and to be honest, as cars get 15-20 years old, main dealers are the last place you want to be!
Emissions, my 2.8 went through its MOT last weekend. She wasn't hot when the emissions test was started as we'd shut her down during the visual part of the test for some other work to be done while on the ramp. It took a good 10-15 minutes and some reving to get the cat proper hot, only then did the numbers go green on the screen. But, the temp gauge was up to normal long before the emissions came down.
As for the air bag, can't help on that as I've never had to look at one.
If KwikFit had MOT'd mine I'm sure she would have failed on emissions as I doubt their testers have the time to wait for cats to get hot. But what you don't know is how hot the engine is if you bypass the oil temp!
@t-tony is right to be "boiling" as the engine may not have been!
Good luck and don't give up on it!