Tohoku itinerary – Where to stay?

We are planning to travel around Tohoku by train and bus in next August and we have chosen some locations we'd like to visit so far. Our itinerary starts in Tokyo and after about 7 to 10 days we want to arrive in Hokkaido.

I'm not sure about the best order of our destinations and where to stay since it would be stressful to book an accomodation at every single location. So we'd like to minimize the number of different hotel stays if it's possible to visit our destinations via day trips.

This is our current plan and I'm thinking of 9 days. Our main interest are shrines/temples combined with nature requiring not the hardest hikes and we also like photography.

1. Tsuruoka/Dewa Sanzan (Mt. Haguro, Mt. Gassan would require a full extra day, right?)
2. Zao: Okama crater, Kaminoyama castle. The fox village also caught my interest but I guess without a car this would be too, ambitious?
3. visit Yamadera and continue to Sendai. Or is it possible to do visit the temple on day 2?
4. Sendai/day trip to Matsushima
5. Hiraizumi: Chuson-ji, Takkokou no Iwaya. Is a Geibikei Gorge boat tour possible on the same day if done as a day trip from Sendai or should you stay the night?
6. Oirase: Not sure about this location but every online guide features it. It seems to be hard to get there and getting around. Day trip from somewhere else (Aomori?) possible or stay the night directly there? Or should we skip this location?
7. Hirosaki: castle and Neputa Mura, hiking in Shirakami Sanchi – day trip from Aomori maybe?
8. Aomori: Nebuta Museum, Jomon village
9. Osorezan
10. continue to Hakodate: the shinkansen from Aomori seems to be the easiest option?

We appreciate any suggestions regarding the order of our itinerary and where to stay or any other tips.

Aizu and Ouchijuku seem to be interesting as well but I think it's conflicting with Dewa Sanzan on the route.

We've seen that there are many onsen locations along the route. Do we miss out on something if we don't visit any of them because we're staying at some onsen location later in Hokkaido anyways?

Thank you!