Three Point Lighting on Green Screen
Using 2 lights with softbox would be great for your background.
The goal here is to get the background lit equally on all sides.
You can use the zebra on your camera to help achieve this.
Avoid shining your background lights onto your subject. That's what your key and fill are for.
Make sure you keep enough distance between your subject and the background. This ensures you have little/no shadows on your green screen. Also, it helps to remove the green spill bouncing back from your background onto your subject.
Please spend twice as much energy on lighting your subject. People tend to spend more time and energy on the part of the image that they will throw away (green screen) and forget about the part that they will use in their film.  
Keylight is a difficult decision and might be different for each project. For a regular MC/CU another light with softbox would be great!
Those reflectors will work great as fill light. Depending on what Keylight you chose. They might be less optimal when using certain LED sources. In that case you might need a second LED as a fill.
We kind of skipped the backlight of you subject. Sure, this is optional. But it could really help your footage to the next level.


Good Luck,