What are Thunderbird's export options?
If it can export as CardDav, then you can import your contacts directly to the Contacts app on the iPad. Just mail the file to yourself then tap/hold on it for an option to open it in Contacts.
I'm not sure about email. What email provider are you using. Most can be added directly to the iPad. If they are IMAP or Exchange services then all your server side folders and emails will be available on the if it's a POP account then you'll probably have to find a third party app that can read whatever archive format Tunderbird uses.
If you don't mind going to Gmail, then it also has the ability to import/export emails, sometimes directly from the account. Gmail works well on the iPad's Mail app, as well as several third party apps if you want a different mix of features.
Good luck.