What's the logic in assigning the type of equity shares ( options ?! / standard shares, preferred..) to founders, investors, co-founders, cto...?

This issue could be something the founders are unable to control. Now it has become a trend that founders (and early employees) can liquidate some of their shares on a Series A or Series B round. Investors found this a necessary step, so the founding team don't think of selling out the company too soon just because they didn't have any money. This article would give you some guidance on the matter (and also a few situations you have to beware of.)

To answer this question, I would need to know a lot more (how many other founders, employees, background of the CTO, etc.). A great resource for thinking through founder equity is this post by Joel Spolsky. http://answers.onstartups.com/questions/6949/forming-a-new-software-startup-how-do-i-allocate-ownership-fairly/23326#23326

I've been a co-founder of three ventures and have had to negotiate ownership stakes with my partners for each one. I've also conducted intellectual property diligence, as a consultant to IP/M&A attorneys, for multiple multi-million dollar software M&A deals. As Stoney said, it's a bit hard to come up with a firm number, given the number of unknown variables involved here. Also, it almost sounds like you and your product are being acquired by this larger company, while essentially selling or licensing a product you've built to this company in the process. If that's the case, you may want to speak with an attorney who's experienced in software licensing agreements and M&A. They may be able to steer you in the right direction of a valuation, as well as make sure you're very clear in what you're giving away, from an intellectual property rights perspective. Another thought that comes to mind is that if the company is providing you with a lot of support, including a salary, be prepared for them to possibly low-ball you on the ownership stake. Once you decide on an ownership stake to suggest, I wouldn't be afraid to start at the high end of your estimate, taking into account the fact that they may try and negotiate the share down quite a bit, given the financial contributions they'll be making. In my experience, investors putting money on the table typically and unfortunately don't value sweat equity too highly or fairly, when compared to cold, hard cash. Always happy to discuss further on a call and good luck!

After shepherding 300 equity crowdfunding raises through our platform I'd say all of them have a higher valuation. Reason is it is the entrepreneur that is calling the shots. It is the entrepreneurs offer on their terms on an equity crowdfunding platform. Once you get outside investors involved shaping the deal the valuation will most certainly go down. Agreed it may then be more realistic as everyone believes their company is more valuable than it is. My advice? Treat early investors fairly. Money is the lubricant to get your idea into reality. Give them a fair share of the business and they will reinvest when need be.

If they are offering equity as your payment then I'm surprised that they didn't come with a number. Or maybe they will. It's hard to give a firm answer because it all depends on how much money the two founders are investing on their own. If you say you'll invest equal portions then you can ask for 1/3 of the company. If you're just investing time, how much time, compared to how much of their time plus equity. Depending on those answers, the amount of equity you're worth can drop pretty low.