Note 1: (passionées)
A French word meaning: passionate, impassioned, ardent, warm, eager. (Larousse's French-English Dictionary.)
Note 2: (Baron Wildenhaim)
This is the part Mr. Yates was to have played in Lovers' Vows.
Note 3: (a poor honourable)
"A poor honourable" refers to Mr. Yates, who as the son of a lord bears such an honorific. Yates might be the younger son of an earl, viscount, or baron--according to: British Titles of Nobility, An Introduction and Primer to the Peerage. If his father bore a rank higher than those three, Mr. Yates would bear a different honourific and probably an honorary title of his own, making him "Lord Something". (One note on "Honorables", according to the link just given here, the term "The Honorable Mr. X" would never be used in speech, the person would simply be introduced and referred to as Mr. X. "The Honourable" is only used when addressing an envelope.)
Note 4: (in propria persona)
This is Latin for "in her own right".