Hello Friend,
Hope you are doing well.
I have seen the requirements mentioned in your bid and I would like to suggest you tha almost all API'S are definitely available in Magento.
Money is not a matter for me but I suggest you to study magento2 documents as all these API'S are available out of the box, except newsletter API which is custom.
Let me if you want me de develop this, apart from this I would like to introduce my team with you.
We are a start up company named Hexcrypto Technologies. We basically provide support for Magento, WordPress, Laravel, CodeIgniter, Cakephp, YII2, AngularJS and ReactJs.
We also provide support for server configuration, email service integration and Linux.
I have a team of 5 Magento 2 Certified Associate Developer who are always available for your help.
Let me know if I can help you in any way.
Thanks.