The scenario would be a startup that will need VC funding, will have co-founders receiving equity, and where each founder will be contributing some cash or equivalent assets.
Here are the ones I typically see. I have also given a point of view on how you should engage legal for each:
Business formation Use legal to review your choice of business entity. Can use to create the business but that has become much easier to do yourself depending on the state.
Operating agreement There are numerous free documents that you can start with and tailor. Use legal to review and ensure appropriateness for your situation.
Intellectual Property (IP) assignment agreement If your startup or founders have IP you will need to work with a lawyer to ensure proper ownership.
Employment contracts You will need for founders and employees. Potential big problems and penalties here if not done right.
Financing Another one that you want high expertise to ensure it is done correctly.
Website / Customer agreeements Many templates available. Tailor and use legal to confirm your situation is being addressed.
Do you have thoughts on what legal firm to use?
I have found that local / regional law firms that have some clients that are startups work best. I would research carefully the online legal factories.
When should I be looking to engage legal support? At the start or after we get some market validation?