Ryanair operate point to point and like most of their fees, the fees for check-in & bags are per flight - so 4 flights = 4 sets of fees,

They do not allow you to check-in for a 2nd flight at the 1st airport nor will they check luggage through.

You will have to pass through immigration (if applicable), collect luggage and recheck-in. If you aren't checked-in in time then its your problem and Ryanair will do nothing to help you - except sell you a rather expensive ticket