My advice is to ask the artists about their rates. Describe what you need and they should have a rough idea of how long that will take them and how much they'll charge.
The choice to do get sketches will definitely pull the price down a bit, but be prepared for the fact that pages may well still come to at least $10 USD or more per panel, so I'd brace myself to expect quotes of $200 and up per episode.
I'd caution against drawing out the anatomy for them if you're getting in the artist because of their drawing ability (even if it's drawing ability in a certain style you have less expertise in). You can definitely supply sketches for how you'd like your panels laid out and where the characters should be in them, which will minimise the need for callbacks to edit drawings already done that interpreted the brief differently, but it's best to otherwise trust the artist to be good at what they do and not get them to draw over your drawings if you want their art style to be the star.
If you're drawing out all the anatomy anyway, your other option is to do the sketches yourself and hire an inker to polish your quick drawings. This tends to be cheaper than hiring somebody to draw.
