Thanks for answering! Re-darkening areas after the fact sounds a lot easier/neater than trying to ink over already-colored pencils - at least for me.
I'm glad to hear that the marker color isn't too opaque over ink.
I think for starters, I might just pick up a cheap pack of basic Blick colors while I'm experimenting (I haven't colored seriously in a *long* time). If I find it fun/effective I might invest in the Copics.