True, thousands of German mercenaries stayed in Quebec for many years. Many of them chose not to return to Germany after the ARW. So, could Philip have stayed in Quebec during the ARW? Afterall, he married a French-speaking girl in 1792.
The documentation that I have presently seems to demonstrate that he was in the southern part of USA during the first years of the ARW. It seems that, he never got above New York, where he first arrived in 1776 with the Waldeck regiment.
From the David Library in Pennsylvania, I have received the hand written muster roll of Captain Alberti of the 2nd Waldeck Company for the period of 1777. Surprisingly, it is written in French. Does this mean that Philip was familiar with the French language?