Is go daddy a good hosting option if I want to start small and scale to hundreds of thousands of users?

Having worked a consultant with global consulting firms and served over fifty of the Fortune 500 companies, I have been a consultant for over 15 years. Although the type of work will vary, consultants need to know why they are being hired. What does your client expect from you? If consultants are armed with that knowledge, they can best apply their skills. I have seen many consultants who jump right into the problem without understanding the context of why they were hired and what success will look like from the client's perspective. A very specific visual that I use is to imagine what the bullet point on my resume needs to look like after I am done. What am I going to do for the client that they can measure and be happy with that I can put down as an example my advice had on the organization. Once I have that in mind, I make sure the client wants that too and the rest is just doing my job. Another thing that consultants may need to know is the type of company culture. If the organization has a lot of certain types of folks, like passive decision makers, the approach to take will accommodate this. The culture of an organization can shed a lot of light on what a consultant can realistically accomplish, especially as the consultant's approach and personality will have an effect on how successful they can be in that organization. I have worked with some organizations where I was not a good fit, while others made working together easy. Being aware of the culture can help the consultant modify their approach accordingly and even know when they may not be the best fit. It is a mature sign for a consultant to read the problem well enough to know that they are not the best person for the job.

When you go with Cloudflare you will have the ability to use or not use the CDN. The great thing here is you can see if your site has problems quickly. Make sure your QA team goes through your site to ensure you find any issues.

In general no effect... and... Be aware all content in subfolders + subhosts is now considered part of domain, so make sure you stick with some sort of common theme across all your content... to maximize your SEO. Also, there's no real way to do what you describe... short of using sshfs or something similar to mount your WordPress site into your EC2 instance, so technically you'll have challenges. Likely best you talk with a Server Savant about what you're targeting to accomplish, before you get to far down your implementation track. Also, you'll have far more flexibility if you dump your .net tech + go with strait up LAMP... Linux + Apache + MariaDB + PHP + WordPress. With .net you'll end up spending considerable time trying to fix technical issues that are unfixable or take many times the hours + dollars required to fix with a Lamp Stack.

If you're using source control, it's easy to track source and control access — or revoke access — if someone leaves the company. Also, your developers should have signed a contract about the project itself that clearly places the source code under your/the client's/the company's control, and if/when they leave, they release all rights to code created under that contract. You can never be 100% sure, but these small steps will at least ensure a legal high ground should anyone steal code. Good luck!

Typically just moving from one server to the next has no issues at all so long as you're not making any other changes to the site, such as changing URLs in a re-design process. Just make sure its a quality, respected server. If the server has issues then, yeah, you'll inherit them. But otherwise you'll be fine.