The names of regiments often are translated into the language of the writer. So in Colin we have references to the Austrian Régiment Archduc Louis (Erzherzog Ludwig), régiments de frontières (grenz regiments) and Russian chasseur regiments (jägers). Valaques is French for Wallachs. In your 1814 example, the "Valaques et Illyrians" are the Wallachian-Illyrian grenz regiment translated into French.
But what makes you think that there were French regiments in the Austrian Army of Bohemia? Count Frederick von Franquemont was a Wurttemberger and commanded a Wurttemberg division in 1813 (the 38th) with Stockmayer commanding a brigade under him. I don't have much on 1814, but I would guess the numbered regiments to be Wurttemberg regiments and the Tirailleurs Valaques to be Austrian frontier troops attached to the Wurttemberg division of the Army of Bohemia rather than a franco-romanian unit serving the Austrians. None of the Wallachian regions ever came under French control and I'm not sure that there would have been sufficient numbers of prisoners/deserters to form a full unit of Wallachians or that such a unit would have been taken intact into the Austrian service.
For the identification of the Tirailleurs Valaques in 1796, it isn;t certain but seems highly probable that this refers either to the combined Wallachian battalion or to scharfschutzen drawn from the Wallachian battalions (parallel to the Croatian/Slavonian Scharfschutzencorps) due to the absence of any reference to a unit with that exact name in Wrede (a massive work detailing all Austrian regiments from the late 17th century to the end of the 19th century).