I have absolutely no experience with YC applications and know almost nothing about the teams that got in.
Given that -- my take:
You are worried about all the wrong things.
Instead, you should worry about whether you are making something people want and effectively communicating that you are doing that. All this other stuff is sapping your energy to accomplishing the one thing YC says over and over again that means the most to them. The second thing is relentlessness -- if you are relentless, these are very minor setbacks, and not worth your attention right now.
Given that -- my take:
You are worried about all the wrong things.
Instead, you should worry about whether you are making something people want and effectively communicating that you are doing that. All this other stuff is sapping your energy to accomplishing the one thing YC says over and over again that means the most to them. The second thing is relentlessness -- if you are relentless, these are very minor setbacks, and not worth your attention right now.