Please note that the following is not meant as a complaint, but is simply to help you gain an understanding of my view point, since it appears most don't know what I mean.
Now, you asked about the modern stuff snd I'd need to run through again, but in a nutshell, I guess it's too refined, too developed, and doesn't show the culture of the area or the pseudo time its in.
For example, let's say he did find a working toilet, it would still be a bit rough. It wouldn't be a well with a hole in it sure, but it would likely be more like a privy than the ones we have these days. Should the dwemer have invented them, why aren't they in most of the ruins? They wouldn't have kept it to just one or two of them. Even should the dwemer have such a developed toilet, it would not have been so amazing, or else would have had their own touch. (like coils that operate it) They don't live in our world, in essence we are living in theirs.
Next, mirrors.. glass is pretty well known and the knowledge to work glass is abundant, (glass cups are all over) yet the knowledge of how to work glass into a strong armor is rare. Despite this, there are no mirrors anywhere.. even in a glass worker's shop. So presumably for some reason, MW and OB don't have them. Although this is not explained, it ends up making the mirrors in your place stand out like a sore thumb saying "hey look, I was very clearly added to the game. I don't really fit in with my surroundings."
The pool table to me is a big one. I don't buy into the logic that because the dwemer where in between the steam age and the modern age they would have had a pool table. By that logic, they should have had fine cigars, playing cards and telephones too. But they didn't did they? Even assuming they had such a table, it would have had their method and culture reflected in it, and not have had a felt covering and an 8-ball.
Saying that these items where inventions that didn't catch on is strange too.. even if they for some reason didn't, they are so different that the empire would have snagged a few for research, and it would have changed the face of lore as we know it. Now, if these modern things were a little less modern, a bit rough around the edges, as though they have a lot of room for improvement, then maybe I could buy into it as the "whims of a wizard" or something, but as it is, it just doesn't blend in.
For all intents and purposes, it looks like you brought the modern day into a midevil world which took a different path, and then tried to have both worlds housed under the same roof.
Just to put something in perspective.. John Michael Kohler invented the fist enameled tub when he enameled a cast iron horse trough in 1883. That's not anywhere near the 16th century, so even modern timing is thrown off, with items coming from different ages. Your blending ages and concepts oddly, and it sticks out to much. If your going to add modernized items, it might be better if they embraced the dwemer concepts so it fits into the game. For example, with a mirror, maybe line it up in a metal that looks salvaged from the telescopes, which simply stands in the room in it's heavy frame, and doesn't appear to have the ability to turn.
I hope that helps.
EDIT:
Just realized I never mentioned anything about your dialogue idea. I think it's pretty neat, but the checks would have to be balanced right. For example, I am an Alchemist even though I am a warrior cuz I like being able to brew my own cures and health etc.. but this means I have high endurance, strength, and oddly enough, intel. Since I play an evil character, I have high speechcraft too, so I can leave dead bodies in my wake.
What this means is I could more or less use all the options you mentioned and win out, so if any depend on more than just speechcraft and the skill (outwit = intel, speechcraft, willpower) then that might be better. As a warrior, I am less likely to have leveled will power too, forcing me to stick to my strong point of rep or something else.. unless I have a high enough speech craft and intel to override the willpower.