Friendly advice from one who got caught early: just ignore those 5* heroes you have, for now. They are hugely expensive and slow to build.
You don’t even have a 3* team built. I’m torn between advising that you just skip straight to 4* or build up some 3s. A solid 3* team will get you through the first stages of the game well. OTOH they are a dead-end: in four months, you’ll only use those 3* for Alliance Wars to fill out your war teams to 30 heroes.
3* heroes are fast to build. I’d look at Gato, cochon, and Mnesseus. Do you have Belith or Hawkmoon? A healer helps.
After getting a decent 3* squad, or if you want to bypass 3*, then you’ve got some great choices. Follow @DMP ‘s advice. Spot on. The choice between Proteus and Tibertus is the tough one. With Grimm, id probably give the nod to Proteus, but it’s a close call.
Again, I think the biggest challenge is deciding whether to build a competent 3* team quickly, or take a slower road to build the long-term heroes now.