My rank:
Offer 3
Offer 1
Offer 4
Offer 2
3 is great because of the compensation and work experience and opportunities to network.
1 is great because management knows they need you. Conversely, it's also why I wouldn't choose 2 since there's no guarantee they wouldn't turn on you at the first bump in the road.
4 is exciting and could have huge upside. I'd need more details to know if large manufacturers could simply replicate any success and kill the company. Economy seems weak in the short term so I'd be careful about taking big risks.