Using the JR Pass next year

Hi there I have a couple of questions.
1. I am travelling to Japan from 04 April 2020 to 19 April 2020. If I purchase a JR Pass before the 10% increase in October this year will the pass still be valid to use when I travel?
2. We are starting in Tokyo for 4 nights, then travelling to Lake Kawaguchi for 1 night, then to Kyoto for 4 nights, with a day trip to Hiroshima then back to Kyoto, then 3 nights in Osaka with a day trip to Nara, then on the last day need a train ride to Kansai International Airport. Which pass, or passes, do I need for these journeys?
Thank you!