If you like your engine at all DO NOT USE STARTING FLUID.

Verify that all glow plugs are good and are receiving voltage. Correct as needed. If the glow plug system checks out ok, I would start looking at fuel delivery problems, particularly an air leak into the fuel system. It's not a bad idea to do a compression check to rule out premature low compression (like you might get from using starting fluid) as contributing to the problem.

On #2, are you talking about a different problem? NSS trouble will make the starter fail to engage. Starting fluid won't make any difference there.

__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.