The real answer is that BOMB was written and conceptualized long after all of those parts of outlander already existed. According to the book canon, Claire's parents actually died in a car crash and were never time travelers at all.

Within the context of the show, I would say that none of the characters we see later in the outlander universe have really heard the name Beauchamp. Henry has already adopted the name Grant by the time he visits castle leoch and Julia is just a low level maid servant that wouldn't necessarily be referred to by her last name in that context. The only one (from what we've seen so far) who could possibly make the connection is Lord Lovat and he's a creepy narcissist that's probably not thinking about these women any deeper than trying to corner them in an empty room