First off, if your acreage is in a drilling unit and "operations" (as defined by your lease agreement) commence prior to the expiration, your lease is still valid and active. Then once operations stop, you lease will still be active for "x" period as per your lease agreement. Ideally in this scenario, your lease would be maintained as active thru the entire drilling and completion process - then (if productive), your acreage will then be HBP (Held By Production).
You are in an active area for drilling - Wildhorse is the primary player in your area. I have not heard of Equisto Resources.
Who are you presently leased to?
20% is way too low in my opinion - 25% should be the going royalty in this area. But you have to get a "cost free" lease so you don't get your payments dinged by various production charges.
I cannot comment on the lease bonus - others in your area need to post on what the going rates are. But $650 per net mineral acre seems low.
If you are in a drilling unit and not leased when drilling commences (i.e. operations start after lease expiration), a whole series of other issues kick in. Others on this discussion can comment on these options better than I can.
My bet is the closer your lease gets to expiration, the more interest you will get and the offers will get higher.
I would even put an ad in local paper advertising that you have 8 net acres open in the area you noted and that it expires in June. That should raise some interest.