Beaty
A Scottish and northern English surname usually linked to the pet form of a medieval personal name, especially Beatrice/Beatus-style forms.
The #2,800 most common surname in the United States (2010 Census) — about 1 in every 23,991 Americans shares it.
Etymology
Beaty is generally treated as a variant of Beatty and Beattie, surnames that were often explained as coming from a pet form of the given name Beatrice or, more broadly, from medieval Christian names built on Latin beatus, meaning “blessed.” The historical sources you provided also connect it with Beatus, which could produce related nickname or diminutive surname forms. In practice, Beaty is usually best understood as part of the Beattie/Beatty name family rather than a completely separate origin.
History
The name is found especially in Scotland and in the north of England, and later spread to Ulster and North America. 19th-century surname dictionaries and regional indexes commonly group Beaty with Beattie and Beatty, showing that spellings were flexible and often interchangeable. In modern records, Beaty is usually treated as one of several surname spellings from the same broader family.
Origin
Regions
Variant spellings
Fun fact
The old reference works you supplied place Beaty in the same surname cluster as Beattie and Beatty, which is a good example of how one family name could split into several standard spellings over time.
From the historical record
“by Robert Bruce Annstrong, p. 184. 1799. Married — William Beaty and Sarah Dana : St. Peter, Corahiil, li. 78. London, II, I, 1 1 Newcanle, 4, 0, o; Philadelphia, 19, r^ rjo.”
— A Dictionary of English and Welsh Surnames, with special American instances