Moroccan lamb tagine - substitute ingredients

[EmGee]

I have a recipe for Moroccan lamb tagine but don't have all the ingredients.

What substitutes can I use for the following:

argan oil
pinttomato juice
cayenne pepper (can I use chilli powder?)

It says to use lamb stock. I have some (never used!) but the use by date was 2011! Do you think I could use it or do I risk poisoning my guests?! If so, can I use a chicken/beef stock (no lamb stock where I am - just veal plus the usual ones).

TIA

Argan oil has a nutty flavour so you might get away with a sesame oil if you have that.
Assuming 'pinttomato' is a typo, do you have any tomato puree that you could water down? Passata? Canned tomatoes that you blend and rub through a sieve?
Cayenne pepper is sheer heat. Chilli powder tends to be a blend. Do you have chilli flakes? Fresh chilli? Hot pepper sauce?
Beef stock will probably work OK.

I have argan oil and the taste is nothing like sesame oil which would be too distinctive, just use olive oil instead.
Use chicken stock or veal, beef might be too beefy, and add spices such as cumin, coriander to taste

Thanks Cogito and Harlot - very helpful!