Obtaining Guardianship of Non-Blood Children when Mother Has Died, Father is Unfit

[Melinda k]

My question involves guardianship in the State of: Missouri
My ex-husband has a daughter who's mother just passed. The mother also has a 5 and 7 year old from a different man. This man may be in jail, he has not been in the childrens life. The mother was remarried, the kids do have a step-father, he does not want the children. The mother has no family willing to take the sibilings. My ex-husband is taking his daughter, my question is: Can my new husband and I get guardianship of the younger two children?

[Mr. Knowitall]

If you're the only people who petition, you're suitable custodians and nobody objects, it's quite possible.