There are two triggers. The AJO3 BR trigger has no bolt release or safety and 1.5 oz The AJO4 has a bolt release and safety. Any Remington compatible trigger will work
As to bases, I suggest a Ken Farrell base. These can be got locally from a number of board sponsors. You want the base that fits the Remington XR100, Model 7 and XP100
A REMINGTON SHORT ACTION BASE WILL NOT WORK.