I'm new to start ups, but have been researching into how much equity/shares I should expect investors to ask for in seed rounds. I have a few questions, though, which I would love answers to as this really is a new area for me.

1. Can the start up company decide on how many investors to take on, or does the lead investor recruit as many as they think is needed?
2. How is the lead investor decided (does the company approach and ask a VC/angel to be considered a lead investor before they approach others, or is it negotiated based on the power/strengths of the various interested parties?)
3. Is there a general guide to how much a lead investor would expect to invest compared to other investors (I've hear about 80:20, and that the lead investor would want 20-30% equity roughly, but I know there's lots of factors involved)
4. Is there any way to see not just who's invested in companies but how much? I can see how much was raised each round and which companies were involved in funding on crunchbase but I'm not sure how public the amounts given by each investor is, since i imagine that's kept in private cap tables?

Sorry if these are obvious/wrongly worded questions. Thanks in advance!