I am in the interesting situation that I am currently exploring two different ideas with two different groups of people. Both ideas are in completely different spaces and I am not sure yet which one I think is more promising. Due to the very different nature of the ideas it's currently easy for me as the potential, technical co-founder to divide my attention between those. Would there be any issue if I applied independently with both separate teams? Obviously I wouldn't be able to follow through on both if they got both accepted, but that scenario seems extremely unlikely to me.
In reality, you won't be able to focus on both. I know people say you can do it, and Elon Musk is a great example of a successful entrepreneur with two awesome companies, but one startup is hard enough on you and the people around you.
My take on this is that you're delaying a decision on what startup to focus on and relying on YC to make that decision for you. In reality, you should work on the startup that you WANT to work on, the one that solves a problem you care for.
This will also increase your chances to get into YC. Being committed is pretty much a requirement to get into YC (or have a successful company for that matter).
My advice is to choose between one of your projects, commit and do everything you can to make it awesome.
