Probably commemorates Frederick Blackwood, 1st Marquis of Dufferin and Ava, or one of his family. See Ava Street for further details.
The Marquess of Dufferin and Ava was appointed Lord Warden of the Cinque Ports with the official residence as Walmer in Kent - in 1891. A very symbolically important honour within the UK. This prestigious appointment is recognised in the naming of several streets off the Ormeau Road.
Resolved - That the names "Ava Park" and "Ava Drive" be approved for new streets off Sunnyside Street on the property of Mr. James H. Dowling. (IC, 24th March 1936).