Starting a Large project

[eluser]Denzel[/eluser]

Is CodeIgniter the right fit for a large project with many parts?

Short answer: it depends. A lot of things factor into this decision. Are you comfortable with CodeIgniter? Would you work more efficiently with another framework? Just to name a few. It's your decision, you make it.

Should I know anything before I go forward with my usual MySQL Database setup?

Once again, it depends. I think you already know this. Many websites use MySQL as a backend, many websites don't. It's up to you to do the research and decide whether it is a good fit for what you're planning. Maybe a schemaless database would do your project wonders. I don't know; it's not my project.

Does it make sense to make these separate CI apps (my current plan) or is there an argument for doing it all in one large CI project?

Sure. You could go either way, depending on the scope of the project and the number of developers working on it.

Any advice or directions would be fantastic. Just don’t want to find out in a month that CI is a terrible idea for scalable apps or some other avoidable pitfalls.

It's a problem when it's a problem. Read that article (written by 37signals, the minds behind Ruby on Rails and a slew of successful web applications). Heck, read the entire book if you have the time, it's a great read.