The one thing that should be universal is that senior/lead developers should be able to mentor junior devs and train them up. If you're at that point then great. Beyond that just have a candid discussion with the prospective employer and have them define what a Lead is to them and what they should be doing. Just don't go in with one idea and get upset that your concept of what a Lead is doesn't match the employer's idea because you didn't ask enough questions during the interview process.
Collaboration: you should know what your coworkers are doing (more or less). Easy "I can prove I did this" mentoring can be something like a Lunch & Learn (teaching about advanced topics in C# or perhaps language features that would benefit the company if they would adopt it). The trendy term "thought leader" is what a mentor does but in a one-to-many instead of one-on-one.
Make sure you can speak about AWS at a high level, but might get tech'd for details.