For me, the harderst part is number 2: not jumping straight to answers or advice.
My instict is to think I can always solve the problems of the other side, especially ones I experienced myself. It tends to be a problem in relationships too 🙃
Loved your tips on that on, the advice about just sharing a personal related story is spot on. Explaining what worked for you, and understanding it's never 100% the same situtation.
A key point I feel is missing, is helping your mentee understand what they can aim for, getting out of their comfort zone. My main experience is with mentoring my employees, and that's a key part of it. If they set the goals themselves, often people aim too low.
Regarding the compliments - this is a tricky one, especially if you don't directly work with that person.
I hate when people 'patronize me', by complimenting on something that's not relates to them. There is a big difference between a compliment from your manager, who sees your work, and someone from outside.
The balance in my opinion is understanding what are the things you know enough - for example, if your mentee did a tough conversation you knew was hard for them. You can compliment on having the guts to do the conversations - but saying 'I think it was a great conversation' is less suitable imo. You weren't there :)