Greetings,
I dont want to say that I am an expert but want to make suggestion to prove it.
Since I have a lot of experience in Zoho CRM+ I would like to tell you that it would be wrong to leave salesIQ for later stage and here is why. When you are preparing email campaign you can make custom email which you can modify with salesIQ service in order to track what happens with client after email (this means that if you adjust well your email campaign you can track what a customer is doing after clicking in your email, which pages he visited and for what duration). So if you have CRM+ subscription I strongly suggest to use SalesIQ parallel with Campaigns and CRM (you dont have to enable chat option on your website, just embed tracking code inside email and website).
Another point is this, its not clear from description do you want form with fields to be filled inside email or somewhere on your website. I guess in email and for this, when someone press submit button it needs to end on some landing page so you will need to develop this with website developer. Also, since today lot of emails are opened in phone you need to adjust it to be fully responsive which is not by default in Zoho CRM forms that you will use for submitting data.
I wanted to bring up some of things that you need to take into consideration to assure you that I know what I am talking about. I have been working on similar jobs and I know most ins and outs of this
I would like to discuss it more.
Regards,
Alex