Next of Kin in Colonial Maryland

It was recently pointed out to me that next of kin in colonial Maryland probate proceedings may provide clues to family relationships.  The Testatmentary Act of 1715 required the presence and approval of "next of kin" at estate appraisals, these were not necessarily direct descendants, but could be any two heirs who might be "in line" (under English laws in effect at the time). Next of kin might, for example, include parents, grandparents, uncles or aunts, siblings, or nieces or nephews (the latter often referred to as "cousins" in early records). And, although the next of kin present did not have to be nearest kin, they did have to be adults; and might be the representative (guardian) of a minor child (A male child was not considered an adult until age 21, but a female was an adult at age 16 or marriage, whichever came earlier).