Hello There,
I see you want to move to Mailchimp. There are so many things we need to discuss in this regard. I'm answering the questions right now. We will discuss over chat.
Answers to your questions:
1. As you want to move out to MailChimp, We can surely do it. Even MailChimp free membership offers 2k emails per day. And 12k emails per month. I HAVE A QUESTION HERE- HOW BIG IS YOUR EMAIL LIST(NUMBER OF EMAILS)?
2. Honestly speaking, No one can guarantee that. BUT, Since you are already engaged with them through Gmail, I will make sure we get more than 50% open rate.(Previously, I have more than 68% open rate).
3. A very low chance of that, We can alternate domain IP so we don't get blacklisted.
Let's discuss details over chat.
Kind regards,
Itzmoni63