What I have at the moment
I have .NET programming skills (C# .NET FrameWork about 5 years), php, html, mysql, a little experience on ASP.NET (+ MVC). I want to get skills and knowledge to develop webservices in future. They can have different functionality, but have following widespread elements on the board:
1. Frontend: landing, user panel, registration/authorization/password recover mechanism, email/sms notifications, ticket/chat support, user data input interface, table/chart reports (+Excel export, compare, sort), billing;
2. Backend: admin panel, databases;
3. Core, running the main user task. As example it can be web data extraction, data analytics, report generation.

All abovementioned elements must be resource scaleable (e.g. with Amazon Web Services or smth like that).

Preferences
At the moment we prefer ASP.NET + MVC, RAZOR and everything about .NET.

Questions
1. What development environment should I use to develop abovementioned functionality? The solution must be:
а. easy to debug;
б. have many free or paid frameworks (as far as I understand, there are frameworks where such functionality like authorization, tickets etc. can be created in several mouth clicks);
в. can create really fast webservice.
2. Can we use .NET Framework?
3. I have not so much understanding in resource scaling, in particular about core implementation. Please advice what information can help us.