Integrate website sign up forms with Mailchimp and Monday.com

Description

We are a small new company and have decided on Mailchimp (MC) as our email campaign platform and Monday.com as our CRM. We also have two websites - a main site, and a second one for training, which also has the facility for participants to create a login and pay online for courses.
We envisage data being added to MC and Monday.com in three ways:
1. Manually, when we are in contact with an individual contact (probably directly into Monday.com)
2. Manually upload a csv file from Typeform, where we have invited individuals to register for a standalone workshop, or asked individuals to provide more information relating to a project we are working on. Some of the fields may be too niche for capturing in MC or Monday.com but the form will still include basic contact details, and the relevant GDPR questions.
3. THE MAIN REASON FOR THIS PROJECT REQUEST: We also want to embed sign up forms into our two websites, and for all the contact/preferences data we collect, to be automatically feed back to MC and Monday.com.  These sign up forms should include the standard contact fields, plus some other fields relating to interests and engagement (in the form of both single down drop selection and multi-selection drop down fields). 
Please note no matter which of the above options is used, we still want all data collected to end up in both platforms by way of a 2-way API to ensure both platforms are always in sync. 
We also need to include the necessary GDPR questions in those embedded sign up forms, and for that data to be captured and visible in both MC and Monday.com. Obviously MC will then manage ongoing GDPR with opt-out, unsubscribe etc. Keeping Monday.com updated with changes as they come through, for reference purposes.
At the moment we have separate basic stand alone sign up forms in both our websites. These are not fit for purposes as they can only collect limited data and there is currently no integration with MC or Monday.com.
We have made a start by creating one of these embedded sign up forms in MC (the one to go into the training website) but we need with the following:
a) embed this form into our training website b) create a second sign up form in MC so that we can embed a slightly different form in our main websitec) make sure MC and Monday.com are set up ready to receive the data from both of these forms d) correctly capture the GDPR component in MC so that our processes remain compliant moving forwarde) create the necessary APIs to ensure the ongoing data collection/GDPR process is automatically synced between both platforms.
And finally, if we could also find a way to embed the data captured via Typeform (option 2 above) instead of doing this manually, this would be an added bonus.