I do not have a good rifle recommendation but here are my thoughts:

Use black powder and black powder only if you are going to be using a flint lock. Use 2F for the main charge (start with 65gr-70gr) and a patched round ball that's the right size for your bore size. You can use 2F in the pan, but 4F is generally recommended to get a little bit better ignition. Do not use a black powder substitute in the pan. It does not burn quickly in open air.

For cleaning, my personal favorite is warm, soapy water. The powder dissolves nicely and cleans right up. Once dry, lightly oil everything. Also, you definitely need to clean your rifle the same day that you shoot with black powder. The combustion byproducts are very corrosive.