Change Adobe plan

The difference will be, that you will go down to 20Gb of cloud space. As for the rest of the tools you name, you won't get penalized. Just if you are using programs like InDesign, Illustrator, Acrobat DC (not the free reader) you need to check other solutions.

To avoid penalty fees, wait until your 12th month of service to change plans. 

See below for details.

https://helpx.adobe.com/manage-account/using/change-plan.html

yes. to make sure that transition is seemless, contact adobe support. there are 3 ways to contact adobe; chat, phone and twitter:

chat:
use a browser that allows popups and cookies
and click here, https://helpx.adobe.com/contact.html?rghtup=autoOpen
in the chat field (lower right), type AGENT
be patient, it can take quite a while to reach a human.

phone:
https://helpx.adobe.com/contact/phone.html

twitter:
tweet @AdobeCare

p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative. ie, double check for an employee badge if contacted in the forums and look for an adobe.com domain in the email address if you click reply to an email. then check again and be very suspicious. any other method of contacting (or offering to contact you) is almost certainly a scam, https://community.adobe.com/t5/using-the-community-discussions/staying-safe-in-the-adobe-support-community/td-p/12919684/redirect_from_archived_page/true