Hi Evan,
Thank you for your post here.
There is an Office Professional Plus 2010 desktop version subscription in E3 plan,you can see Office 365 Plans and pricing.
Q1:How easy or hard is to import our email and contacts?
A1:Based on my experience ,it's not very hard to import emails and contacts.
Please see Migration or PST Import emails to Exchange Online and Import Contacts .
Q2:What happens to my google apps account? Will I still renew my domain with them?
A2:You don't need renew your domain, only need change the MX record that point to Office 365.After that the google apps account can't receive emails.
Q3:I have a user with google apps that is no longer active but I still need access to his email. Can I import his email without paying $20/month for him? I still need to receive his emails but do not need to send from his email.
A3:Office 365 can import in use account emails.
Q4:What happens if an user leaves in the future? Can we access his email without paying the license fee every month?
A4:You can cancel the user's license if there is someone leaves.Before canceling the license,you need export his emails into a pst file.
Q5. Will the web version of outlook sync with the desktop version?
A5:Messages will be synced between server side and client side.
Q6:Can the admin easily access the other users email accounts?
A6:The admin can easily set the other users email accounts,and the admin don't have ability to Open and View the Contents of a User's Mailbox by default.However,the admin can assign an administrator the permissions necessary to open another user's mailbox.Please see Give an Administrator the Ability to Open and View the Contents of a User's Mailbox.
Thanks,
Keats Ge