A child is not an asset like a house that gets willed to whoever you choose. In these situations, a court and/or child services will protect the child's rights and well being, if there are no legal guardians. If the child's mother has died, you are still one of the two legal guardians. If your mother becomes the second, that doesn't mean you stop being a legal guardian. If your mother then dies, you are still a legal guardian. The two slots do not have to be filled, one is enough. If you are stripped from your parental rights, your mother adopts, then dies, then the court will decide. If she wills that you again become a legal guardian, that does not undo the stripping of your rights.
Explore your eligibility to adopt a child. There is not a constitutional right to adopt a child. As a result, all adoption rights, procedures, and requirements are governed by state statutes with some guidance from the federal government. In general, under current state laws, any single adult or married couple is eligible to adopt if they meet certain criteria.
So when exploring ways of controlling the cost of an adoption, one has to ask if all of these lawyers are really necessary. I am told that there is no legal requirement to seek legal representation. A quick search of the internet will try to convince you that there is but the majority of these websites are owned by attorneys. Of course, the laws differ in each state and so it is incumbent upon those involved to ensure that they are aware of their particular state laws and are in compliance with them.