Hi John
I respect your inclination to not be influenced by others writings and to reach your own conclusions which of course is an acceptable and meritorious approach.
I believe the furniture in the room would probably have been cheap pine or a similar wood. While I do not think the Expressionist painter Walter Sickert was the killer,
as has recently been alleged by Patricia Cornwell on weak evidence, some of Sickert's work and other artists' paintings show working class rooms of the period. Here is a working class room as painted by Sickert as well as a photo of the artist himself sitting on a chair--

Sickert, "Ennuie" painted circa 1914

Walter Sickert
You mention that you are in Australia so may find it difficult to see working class type furniture of the day. But how about reconstructed Australian colonial era settlements? I am sure there must be a few around that you could visit or even find on line.
John, there were no sounds reported of the furniture being moved around on the murder night. We have reports of Mary going in and out of the court observed with various men. Also one witness reported hearing the cry "Oh, murder!" during the night.
It is probable that the bed was moved to take the photographs, at least certainly the smaller photograph looking toward the door. You could be right that the killer was a smaller man, or at least not a big man. One of the best regarded suspect sightings, that of Joseph Lawende who saw a man with Catherine Eddowes prior to her murder, was a man of a man aged about 30, fair complexion, brown mustache, height five foot seven with a gray peaked cloth cap, red neckerchief, salt and pepper coat, sailor-like appearance. Such a stature, five foot six or seven or so, of course, would have been average for the day.
When you talk of a bedside table, there was a bedside table with various organs on it, next to the door, left side of the bed, and the washstand that I mentioned in my last post to the right of the bed. I am glad you agree with my view that there was likely a gap between the bed and the back wall. Have a look at the dissertation by the Viper
"The Whitechapel Dossier: Dorset Street and Miller's Court" which discusses the dimensions of the room and shows the plan of the room that I mentioned earlier. A new dissertation by Simon Wood
"http://casebook.org/dissertations/room-13-millers-court.html" contains some interesting ideas about the placement of the furniture and the bed in the room.
That back wall, incidentally, was just a thin partition separating the murder room, 13 Miller's Court, from the front of the house that faced onto Dorset Street. John, your theory that Mary, a prostitute, would have wanted her furniture away from the walls, to lessen knocking against the walls during the "act" is a very good one.
In regard to the idea that the Ripper had sex with his victims either in life or necrophiliac sex, the jury seems to be very much out since the doctors' reports fail to mention evidence of any connection. It could be therefore that the killer was impotent, which is one of the things that might have fed his rage.
Last, we have no evidence that the bed rested on the tin bath evident under the bed -- the tin bath was simply sitting under the bed, I believe.
John, I hope these further thoughts prove helpful to you.
All my best
Chris