If you’re not too concerned about typing in your current master password into the online version of Bitwarden’s interactive cryptography tool, then I would suggest that you just use the online form with your real login email and master password, and copy down the value of the “Master Password Hash” that you get both for the old number of KDF iterations and the new number of KDF iterations.
As I had proposed above, please send those two hash values to Bitwarden’s tech support, and ask them to validate these against the hash stored in their database for your account (they would have to run the server-side iterations first, but I assume they will be aware of that). Let them know that you plan to delete your account in the near future, so that they are aware that there is a short time window available in which to check the hash values. I’m still hoping to get some word from @bw-admin that tech support will play along. It may be a good idea to give them a direct link to my response here (https://community.bitwarden.com/t/help-changed-iterations-and-can-not-log-back-in/49958/51).
Yes. And go easy on those KDF iterations. 
You will get more protection by simply adding a single-digit number to your passphrase (if you randomly select which word to append the number to, and randomly select the number).