It must be a mistake. Ryan, the lowest common royalty other than a specialty interest such as an Over Riding Royalty Interest (ORRI) was one-eighth or 12.5%. That is the historic beginning of wide spread oil development about 100 years ago and has improved over time. Modern royalty is in the range of three-sixteenths to one quarter but as more and more development is concentrated in unconventional reservoirs that range is one-fifth to one-quarter.
I could be but there is no way to know without more information.
Not bad but could use some negotiating. I prefer 3 year primary terms but would strongly consider 5 for a better royalty and bonus. Personally I would accept a 22.5% royalty and $500/acre for 91 acres. It would be good to know the energy company behind the offer and royalty and bonus are not the only important terms in a lease agreement. You've got enough at stake here to consider the assistance of an experienced O&G attorney.