Removing the lifters with the engine in situ is easy. How can they fall into the pan when there's a cam in the way? Just pull the lifters before you remove the cam. A long-nosed snap ring plier will do the trick, or even a regular needle nosed plier. Expand the tool inside of the lifter, and gently and smoothly pick it straight up. Generally no problem.

You will need to disassemble quite a bit of stuff, though. Budget a decent amount of time for the job.