Maybe "A senior engineer should support their peers" and "A senior engineer should empower their peers through their career track"? and I think those should be mandatory for a good team lead, but they don't really hurt in a senior either. I think the article focuses a lot of one definition of senior who is a good team player as well and not the star coder/hero of the team who pulls all-nighters and whose code no one understands. There are some areas where you need these people, but I'd rather go with the team players most of the time
I think "A senior engineer should be a motivator for the rest of the team" is a bit odd, but maybe rephrasing it to "A senior engineer shouldn't be the one complaining all the time.", if I was hypothetically speaking about myself :P