I want to join DOT

These are the characters I have. I am planning to build a DOT team but my friends suggested me not to because I need to invest a lot of resources to have a functional DOT team. I obviously want to start with kafka as she is the main core of the team (I lost every 50\50 on her banners). I will be pulling her after I secure phainon. Can i have like a functional or semi-functional team with characters I have? Or is it like a premium follow up team where you need all premium units for them to really shine.