Need advice on analog signals from motorcycle.

I'm wanting to install a screen as my dashboard . This project is a collaboration with a couple buddies who will be doing the design of the gauges and interface of the dash. We will probably use a 7 inch tablet first to see how it works. I'm wanting to use a raspberry pi because of future additions but I think I need a arduino board for the sensor signal at the back of the factory dash. The sensors we are going to use at first are already at the factory dash. I'm in need of suggestions on the best way to convert the analog signals to digital . I wish it had a obd2 port but no dice as that would have made it easier.

Any and all suggestions are welcome and thanks in advance for replies.

P.s. I'm new to this but can usually work my way through if I have a better source or direction.

Can you explain what kind of measurements you want to make and what precission and accuracy you need. Also how often should a measurement be made. These are the basic questions to answer and are an indication of the sensors you could use. E.g. for temperature there exist digital and analog sensors that have a different working ranges.

I hope you are prepared to deal with raspberry pi. What I mean is that in order for the rider to turn on the dash and go, you need to daemonize your program at least. Then the pi turns on and runs your code like a service or driver so nobody needs to log in to the dash display LOL! I am still struggling with this portion with a camera logger project using pi.