Merry Christmas to you as well!
Yeah, scenes vary depending on what your "relationship" level is with each girl and which State they're in since the game is based on progression (slowly building/changing the characters).
Thing is, there's a few scenes which seemingly are a one-time only show, meaning that they only show once and yield no notable/perceptible changes to the story whatsoever but might foreshadow things to come (like Lucile's scene where the dog snifs her).
Now for the Martha Bathtub, someone snapped a pic of the part during the flash (can't link to it tho cause I don't remember the page or who posted it) but for a frame it shows Martha with glowing white eyes akin to Doyle's. At this point it should be kinda clear (if we're to believe this is a tidbit of untold story) that Doyle is doing something else besides helping you bang your family but we've yet to know what happens next. A hint to what he wants to do is when you discover he's now visible, the MC mentions that now Doyle is closer to going to heaven or whatever and Doyle is like "What? Oh yeah, Heaven and stuff..." clearly backing off from his original plan (which knowing Doyle was pure bullshit to convince the MC to help him) but he still needs to put a facade to not raise suspicion.
For that matter as well and I might be stretching things up as we have no further proof, but my guess is that Doyle is trying to bring his own family back somehow and the one possessing Martha wasn't him but his own mother as the part of "extra dinner" seems unlike Doyle and appears a more motherly gesture than anything. Granted this is just my theory, a GAAAAAAME THEOR--- ok, nevermind. But yeah, that's my theory about it. Don't know if next update we're gonna get something story related (in general, not exactly for Martha) so we all have to wait and see.
