I do not have too much to note on this story, more fun questions to consider. Please feel free to post your own facts in the comments and if you wish, to discuss anything in this post :-)
1.) Viability of the plan
As Holmes says in the story this is a singular & peculiar case., "...the course of events is certainly among the most singular that I have ever listened to."
The curious approach used to free the shop for excavation of the cellar is both ingenious and audacious, and one I admire.
Yet...I always have pondered at how it succeeded. Admittedly it was tailored to answer the particular qualities possessed by Mr Jabez Wilson, however, the apparent amount of interest generated would surely result in some notice from standers by or a journalist?
Social media didn't exist to spread the news about admittedly, but the number of disgruntled unsuccessful applicants plus anyone in the nearby offices would surely remark upon the bizarre affair?
2.) Financial backing
Considering how much they paid Mr Wilson a week (£4 in old money, which was roughly £328.20 in 2017 according to the National Archives site: https://www.nationalarchives.gov.uk/currency-converter/# - disclaimer that is a rough estimate and should be taken into context of trying to adjust for inflation and so forth; there are links to an inflation calculator at the bottom of the page for enterprising souls)
This also suggests the criminals had sufficient funds to even begin matters, which most probably originated from John Clay due to his family lineage.
However, I think this is why I enjoyed Granada inserting Moriarty into the tale, as it became more believable in the sense of a financial backing/framework existing to begin the affair.
Interested to hear people's opinions!
3.) Latin. "Omne ignotum pro magnifico."
My school girl Latin is long gone so thanks to Granada for the translation:
Everything become commonplace by explanation
Though Holmes does complain it is a loose translation!
Poor Holmes! I had a good chuckle at how Mr Wilson declared how unremarkable his deductions were, & missing the point that such deductions are tied to acute observations and possessing the knowledge to understand what is observed.
4.) Tattoo: Another instance of Holmes showing one of the specific & narrow fields that he excels in. I am curious of how he contributed to the subject, and whether this was done before meeting Watson?
5.) Date
According to Watson (through Mr Wilson) this tale is set end of June 1890 since the newspaper article is dated 27th April 1890.
However, this contradicts Watson's opening statement: "I had called upon my friend Mr Sherlock Holmes, one day in the autumn of last year…"
Then later on it is noted that the Red-headed League was dissolved 9th October 1890. So the autumn date seems to be the accurate one instead of end June for the events of the case. How do we explain this?
Externally, it is likely Doyle mixed up dates during the course of writing.
Internally, this is another "Watson is unreliable narrator," occasion and fun to consider. Why would Watson fudge the dates? Was he attempting to protect someone through muddying when events occurred?
6.) Assistant - Vincent Spaulding
Mr Wilson. "...have a job to pay him but that he is willing to come for half pay."
Mr Holmes. "I don't know that your assistant is not remarkable as your advertisement."
Of course Holmes is correct and I think that this obliging man was a curious fact highlighted in Holmes' brain for quick reference once he had heard all the facts from Mr Wilson and during his investigation.
7.) Mr Peter Jones of Scotland Yard
Do we ever come across this police agent again? Is he an Inspector? I found the terminology Holmes used curious.