Hi Fryerning
1) Apparently when William Titley died in the men's home, his estranged wife Louisa & adult daughters had no idea that the surname Bell was an alias, and had never heard the surname Titley mentioned. The news caused much angst, probably because of the issue of bigamy.
2) William is listed as Bell on all of the documents related to Louisa and his daughters - all of the WA documents I've found. I understand the documents identifying him as William Titley, with a family in Victoria, were only found amongst his possessions after he died. My grandmother did not have these documents, so I guess they are lost to time.
3) Yes, McArdle was Grace's 3rd marriage. Her final marriage was to Raymond Shields in the early 1950s, and they were married for around 20 years until she died in 1973. I'm not aware of any other marriages but there were also at least a couple of de factos, where she used her 'husband's surname. I don't have any records of these.
4) Louisa was already living with John Smith in a de facto relationship when William died and she married John soon after.
5) Grace had told me that the Harp vs Harp case led Louisa to leave William. I liked to check her stories when possible, so I went to the Battye library and found a newspaper account of the preliminary hearing (think it was on microfiche - this was around 1970). Unfortunately, I only took brief notes. It was John Harp vs Julia Harp, co-respondent William Bell. Unfortunately, I did not note any details of the newspaper, apart from 117/1919. Obviously 1919 was the year, but I don't know what the 117 referred to - could be part of the library call number.
6) I've attached scans of all of the certificates that I have:
marriage of Louisa Florence Riley to William Bell 1891
birth of Grace Florence Bell 1903
death of William Titley 1933
death of Louisa Florence Riley 1944
Leigh