Southern Transylvania was Orthodox in 1850 (first map above) and 1930 (second map below):
Whereas apparently all of Transylvania was already under Hapsburg rule by 1700!
The Hapsburgs briefly controlled Craiova, in western Wallachia, in the early 18th century, so I do think that having the Hapsburgs control Wallachia is probably more realistic than having the Hapsburgs control Moldavia (other than Bukovina).
Would a Romanov-puppet Romania count for this? Because that's what Catherine II apparently wanted with her Greek Plan:
https://en.wikipedia.org/wiki/Greek_Plan
I suppose that we could also see a direct Russian annexation of all of Moldavia while the Neo-Byzantine Empire led by a Russian...