Need help to get an overview of business software for crm and email

Hey all,
I am looking to improve our software for our company that offers meeting and event spaces.
We have 6 employees and some freelancers that sometimes need to be integrated in the software.
Specifically I am looking for software that can:

– automatically create an offer and a customer out of an e-mail (from our existing contact form) and save it in some soft of database (for newsletter)
– track the status of offers and payments and mark it in a calendar
– send automated reminders to customers when not responding to our offers
– option to convert an offer into a bill
– a simple e-mail software with accounts for every employee and an account for our finance chef to see all e-mail communication
– integration into a calendar like google calendar
– to-do lists with reminder and notifications for chef when to-do is done
I would really love to get some help as there are so many systems with different features and it's hard to get an overview.
Thanks for every help!