What is the best fix for Remington rifles? Is it just a aftermarket trigger? Would a 3 pos saftey make it any safer?

First, It isn't broken. But the best and least expensive thing you can do to insure the trigger functions properly is have it periodically cleaned and serviced. You can purchase the new X Mark Pro trigger for about $90.00 which incorporates a trigger blocking safety, and, has done away with the separate connector, and I might mention, kicks the snot out of any non competition type aftermarket trigger, or, if you are not comfortable with the idea of the separate connector, you can perform a simple modification to the one you have and grow old with it.