Here are some thoughts from me:
Do these make sense or is there something I'm missing?
First, I recommend this other discussion around finding a mentor which covers (and agrees with) some of the tenets of your question: "How do I find the best mentor for me within my company?"
Moving on, I think #1 and #3 are 100% correct, but I actually don't agree with #2. While a mentor outside your org can work, I haven't really seen the bias thing come into play (a good mentor should be honest no matter where they are in the org chart relative to you). This is why I heavily prefer having a mentor from within your org, ideally within your own team:
How do you typically find a mentor at Uber? Is there some sort of matching process? Your criteria seem fine to me (though I like Alex's point about a mentor in the same org), but I wonder if a better question is "how can I best present myself to be mentored?"
I've seen that entering into the relationship is harder than finding the right mentor. The best mentor-mentee relationships are those where both sides feel like they're getting something.
If I'm a Staff engineer, what I'd look for in a senior eng to mentor is:
So your job is to show these traits in your outreach or interaction with possible mentors.