Hi, at PRDH I found the various spelling for both Richer and Richard. I copied/pasted those lists below. These spelling variations come about because most people back then did not know how to sign their name. The number next to the various spellings was the number of times that spelling was used in Quebec between 1600 & 1799. For research purposes, PRDH and most researchers use the most common spelling.
According to the list, before 1800 there was never a cross between Richer and Richard. Notice that the variants for Richard all have the “ar” sound. Most French clerks would have picked up on that sound even if the individual could not sign. Back then no one cared how their name was spelled. I am not even sure how Richer is pronounced, well I guess I do, but it sounds foreign to my US French/English ear.
Once the descendants of our ancestors, moved to the US, they were at the mercy of English speaking clerks, so even more variants came into play. Janet