Capitalization after colon and semicolon

Hello, I am writing an essay and I have never known how to properly use colons and semicolons. I want to write that something is challenging, and then provide a list of three or four reasons (which will be complete sentences) why such thing is challenging. For example:

When thinking about making this concept a reality one faces many challenges, namely: (1) A tremendous amount of  heterogeneous data is constantly being produced; (2) Such data’s origin could be unreliable and the data itself can be imprecise, so pre-processing of data is needed to remove inaccuracies and security measures should be provided; (3)...etc

Should I use a capital letter after the colon? What about the semicolons?

Thank you in advance.