Kansai Mini Pass

Hello,

My friends and I are excited to be traveling to Japan for the first time, and we've obtained the Kansai Mini Pass as part of our travel bundle. Here's our itinerary:

Day 1:
- Arrive at KIX airport
- Travel to Dotonbori
- Visit Team Lab (and return to Dotonbori)

Day 2:
- Explore Dotonbori
- Visit Osaka Castle
- Travel to Nara
- Return to Dotonbori

Day 3:
- Travel from Dotonbori to USJ (and return)

Day 4:
- Journey from Dotonbori to Kyoto Tower
- Visit Kiyomizu-dera (and return)

Day 5:
- Travel from Kyoto Tower to Fushimi Inari Taisha
- Visit Saga Torokko Station
- Explore Bamboo Grove
- Return to Kyoto Tower

We plan to use the pass from day 3 to day 5, but we're unsure about using it to get to Kyoto from Dotonbori. Additionally, we have oversized luggage and are wondering if we need to make reservation. Also, is the Tokaido-Sanyo Line covered by the pass?

Thank you!

Regarding the pass, I suggest you look at the JR West site:
https://www.westjr.co.jp/global/en/ticket/pass/kansaimini/

Please note that any ltd express trains are not covered, but you can take rapid trains. Also you can take the JR loop line in Osaka, but not the subways.
You keep mentioning Dotonbori. I take it that's where you are staying? As a place it is a lot of fun, but it is way better in the evening.
https://youtu.be/COJ_MeXbeow

Osaka has other good places as well - great night views from the Umeda Sky Bldg & Abeno Harukas, plus Sumiyoshi Taisha is one of the better places there. Osaka "Castle" is worth a walkaround, but it is not a castle nor a re-creation - just a museum with a castle facade. If you have the time, go see Himeji. Some good places to eat at Shinsekai also.

Your Day 4 doesn't make much sense - you go see Kyoto Tower (which is really old school and not that interesting now - I went there for the first time more than 40 years ago), and then off to Kiyomizudera. The tower doesn't take that long, and Kiyomizudera might take you 90 minutes but depends on your interest. That leaves most of the day empty. There is loads more to see - the Higashiyama area is loaded with great places, and all packed together.
For Day 5, Fushimi Inari is not too far away either, and is one of the icons of Kyoto. You could spend several hours there if you wanted to. But the bamboo grove is on the other side of the city, you'll be done with it in half an hour, and it's not clear what you're going to do at the station. Arashiyama has lots of good places though - Gioji, Okochi Sanso, Adashino Nenbutsuji, Otagi Nenbutsuji etc. You need to plan things out more.
https://goo.gl/knQtMg

Just get a IC card. You need non JR options in you travels. And other non JR travels will be quicker to get around than JR options.