It is certainly possible. But it's a lot of work.
Have to remove both timing belts, and the camshaft, and all 12 cam followers and valve springs/retainers/keepers, then put it all back together afterwards, including two new cam seals and the full timing belt installation procedure.
It is indeed easier than removing the head, though, IF valve stems seals really are all that's needed and if you are sure they are problematic now. For what it's worth though, those are not a very common issue. Are you seeing oil consumption that you have traced to the valve stems/guides? If not, it would be a lot of effort for something that might not give you any noticeable benefit.
Checking valve clearance is quite a simple job by comparison -- only have to remove the valve cover and use feeler gauges. No messing with the timing belts (unless they are already due anyway), no removing the cam, etc. If they need to be adjusted then it is more involved, need the shim kit and special tools to do that, but still pretty simple. There isn't really any overlapping work between valve clearance check and valve stem seal replacement, except maybe the removal and reinstallation of the valve cover.
Is there an issue you are looking for, or is this just for preventive care?