I think it really depends on which tank you want to use and how your emblems stack. All the suggestions above would work. I think chose which tank you want to use and max it based on that. With frigg, alfrike, ursena, and heimdahl on your roster, and of course Telly, you have great possibilities.
My defense that @JAWS1 mentioned is holding 2550-2625 depending on the day. However after two weeks I dip down 2550 more than I’d like. I think it would stay about 2600 if I had frigg maxed. I had Guinevere in for a week and that team did worse. I have consider doing alfrike too.
If you put a ninja on defense, I think they should be flank.
Overall you have lots of choices.