on the lifters? take the valve covers off and take them out, clean them, and just use assembly lube. im sure grease will dissolve into smaller particles that may block the oil passages, but then again its only grease and the oil pressure should be enough to dislodge it if it were to ever block anything. if you dont want to take it apart, just run it for like 20 minutes and then change the oil and filter again.
I doubt it. May cause some stickieness though. If i were you i would run a thin solvent such as seafoam through your engine before your next oil change. this may help move it out of the way so that fresh oil can take over.
