Hi Dawud.
Wow, that is a LOT of issues! My first thought is if you bought from a dealer, go straight back and start quoting sale of goods act. If it was a private sale I would be looking for an auto-electrican with Jag experience. I did a quick search and based on your profile location you might give these guys a call: https://autotektuning.co.uk/
On the cambelt it is needed ASAP but I would want to make sure the electrics were sorted first before I fork out several hundred for a cambelt change.
Good luck
John