There is for sure more solutions, and more advantages and disadvantages for each solutions, but these are what came to my mind.
What do you think and what is your suggestions? Is there any fifth solution which you can suggest? What are other advantages and disadvantages of each of the above solutions? Is this idea attractive for an investor at all? For example, for your self! Would you ever invest in such idea? And why?
I am kinda technical person with years of experience in developing custom solutions for my customers. But I was never in place of being an entrepreneur and I think my knowledge in this field is really nothing. :-/
note: sorry for question almost-duplication. I changed description based on my gathering in last week and repost question to hopefully get an answer.
I have read your post several times. The fact that no one has answered yet is a sign: your situation is confusing. That's also probably why you are not making any progress.
Can you clarify: if you did complete an MVP, what did it achieve? The whole point of an MVP is to go from idea to something you can pitch and sell, and iterate with. You seem capable since you made your MVP yourself. So what is preventing you from making progress?
Now, to answer your list of possible next steps:
1. Find a co-founder or investor: these are such different animals, never put them in the same bullet point. Yes, it's hard to find someone to do all the selling for you (it's hard work). What you should be doing is pitching everyone you can get your hands on. If no one cares about your product after 3 months, that's a big sign that something is wrong: your pitch, or your product.
2. Open sourcing: that's usually never the solution to lack of interest. Your current problem is that no one cares about what you have built. You can dump the code on github and nothing will happen.
3. Crowdfunding: crowd funding works really well for consumer products with attractive videos. Based on your confusing explanations so far, it doesn't sound like you'll be successful there.
4. Send proposals to big companies. Yes, but not the way you describe it. You need to find interested users. Finding customers is just as much a skill as software development.
So in conclusion, I'd combine #1 and #4: you seem to be most in need of a reliable sales person to land your first customers. Good sales people are very hard to find. Try to get as many meetings as you can with people in that industry and do both: pitch them, and ask them what their pain points are. Hopefully, your product solves a problem for someone. So far, you haven't shown that.