Help me veganize this "ancient" German nudel salat (spaghetti salad)

I want to veganize this wet salad recipe.

1. Probably gonna replace the spaghetti with beans, at least once I've done a test run.
2. I'd like to partially or completely replace the mayo with something less fatty, maybe cashew? Hopefully some black Himalaya salt can emulate the egg flavor.

• 500g (17.5oz) spaghetti (dry weight)
• 600-700g (21-25oz) smoked sausage (about 1/3" pieces?) - Seitan w/liquid smoke, probably.
• 5-7 hard boiled eggs (diced/chopped or mashed even) - nothing I guess
• 3 apples (chopped)
• 1 tbsp mustard
• 300-350g (10.5-12.5oz) mayonnaise - I figure using a cashew based cream I can replace both mayo and egg at once. Might add some mayo or oil if the salad needs fat.
• 500-600g (17.5-21oz) pickled cucumber (vinegar, not brine - chopped)

Stir in some milk if the salad starts getting dry.

I'd love some instructions on the mayo/egg replacement, as well as the smoked sausage, to make sure the chances of success are as high as possible on the first try.