step dad wants me and siblings to sign waiver of inheritance

Location: Oklahoma
Around may my mother died, leaving no will but she did have a life insurance policy and a house worth 68 thousand in her name. Originally before my mom passed on her death bed, she told us to use her life insurance money for all us kids to go on vacation, that didn’t happen. My step dad proceeded to use said life insurance on meth and his new found girlfriend. Any how he was told the estate has to go to probate and started asking me to be executor because he legally can’t (He’s a felon) this is where stuff started rubbing me the wrong way. My step dads lawyer filed a motion to appoint me as executor (the hearing is scheduled for august 14th) But during this time his lawyer also told us kids that we need to sign these waivers and get them notarized before the court date appointing an executor that state the following;

X, heir of the Estate of (mom), as determined by Order of the

District Court filed herein, hereby waives any right and claim he/she may have to any share of

the estate that he/she may be entitled to in the Estate of mom

2 of my 3 siblings have already signed, i’m weary to sign because i don’t know what i’m giving up.
the house is estimated to be worth upward of 68 thousand dollars , and i was told by said step dad that the reason we have to sign it over is because he isn’t on the deed due to trying to dodge child support payments (so my mom was the only name on the property)
ideally should i sign to keep the peace or wait until a full accounting of assets is finished? and am i wrong for thinking something is fishy?