Hi @mgavenda
It sounds like steps 1 - 3 are already happening. You have a form, which creates a ticket and sends an email.
Looking at the fact that you are sending out the marketing email from Hubspot you set the reply email to an integrated inbox, and the response will be logged to the contact record and the associated records as well.
All you need to do is set the reply email address to be an email address that is in a connected conversations inbox and not a personal email address.
Alternatively you are able to get the person who receives the response to log their response email to the client and associate that to the ticket, this depends on whether you need these emails to go to one inbox or to individuals.