Thanks for taking time to read my post and sorry for the loaded questions -- please read patiently to help me. Here is the scenario:
Founder has the startup idea vetted 3.5 years ago -- but never funded. Recently the stalled venture is showing signs for attracting investors. There are two working partners who entered the scene just now. The venture has three phases. Phase 1 r&d. Phase 2 development and phase 3 tracking.
Q: Is it appropriate to call new working partners ...
A: You can call them anything you want. I would agree with Alain that they are working pre-money, then they theoretically can be called founding members.
Q: How much equity / options for a) full time technical person and b) marketing person @ 25% time.
A: How to Divide Up Your Company's Equity - flavor to suit your condition.
Q: What % equity does 500K get?
A: Just like the show dragons den / shark tank, it is whatever you negotiate and they accept. Could be 20% - could be 70%. If you don't have a compelling offer, likely it will be zero.
Q: What are the questions to ask an investor? When do you ask for a term sheet?
A: You can ask all you want - but you won't get anywhere. Most of the time you are there to answer their questions - Investors expect you to be prepared. Term sheets are offered - not something you ask for. Suggest jumping over to venturehacks archive section and learn all you can.
In the future, if you break up the questions you'll likely get better answers. Best of luck.
For term sheets, read the Brad Feld term sheet series