Briefly, the newly re-established facts:

Jenny Lind (1820-1887), the celebrated soprano and wealthy philanthropist, meets Chopin many times in London in May-July 1848 as documented by his upbeat letters.  She tells exited a friend on 4 September that she is discussing a project with “one of Mendelssohn’s most intimate friends”.

Jenny Lind obtains a blank marriage allegation form stamped "London 28.9.48" and meets again with Chopin in Edinburgh.  Her letters and 1891 Memoir confirm the exit of her Swedish fiancé "G" by early October 1848.  Alone, Chopin walks the corridors of Calder House "with my doubts" (16 October).

In Chopin’s letter of 30 October 1848 to Wojciech Grzymala, Jenny.Lind fits the description of the unmarried “rich” woman, who is “too much like me”, and who should rather marry a “young and handsome” man. Chopin seems to refer to a young woman who can “sing”, as he ponders what happened to his "heart" and "strength". 

Jane Stirling (1804-1859), the Scottish spinster and Calvinist guarded by her elder sister Katherine Erskine (a widow since 1816), does not match Chopin’s above description of the “unmarried one”.  She was not rich and young;  nor could a "young and handsome" man have found her attractive.  Living on ca. £ 300 p.a, she could not have afforded to assist Chopin financially (e.g. 25,000 frs in July 1849, which beyond any doubt was an anonymous gift from Jenny Lind).

Evidence includes the will of 1816 of Jane Stirling's father* and her own will of 1859, her docile letters from 1850-1851, and her death certificate.  A.E. Bone (p. 100) cites Jane Stirling as “a hoarse-voiced, restless, invalid Scotch lady of some rank, mostly wandering about on the Continent” (quoting Thomas Carlyle in 1850).¹   Chopin wrote often about how "boring" he found the two Calvinist sisters.**

Previously manipulated and embellished:

No evidence exists to suggest a romantic relationship between Jane Stirling and Chopin.  Jane Stirling's acquaintance with Chopin in 1848-1849 has been distorted or embellished  by certain writers. – Notably:  In 1888 by Frederick Niecks citing rumours from 1844 and hearsay from 1848;²  in 1900 by James Huneker (downplaying Jenny Lind, citing Niecks on Jane Stirling);  in 1931 by E.L. Voynich, the strange translator of Chopin's Letters, who placed a misleading footnote;  in 1932 by Martial Douël making, in a respected journal, the baseless if not preposterous claim of Jane Stirling being “in the lead” of “all of English high-society”;³  and by Bronislaw Edward Sydow (1953), A.E. Bone (1960) and Arthur Hedley (1962) publishing incorrect and misleading translations of Chopin's letter of 30 October 1848.*** 

Arthur Hedley, a noted English scholar and Chopin expert, goes even further to embellish Jane Stirling's acquaintance with unfounded statements in his 1947 biography of Chopin (p. 112).  For example, Hedley misuses an out-of-context and erroneous quotation of Jane Welsh Carlyle's letter of 4 August 1850 to raise the notion of 'Chopin's widow dressed in deepest morning'.¹  A.E. Bone duplicated this feint in 1960 (p. 61).

Evidence points to Jenny Lind as the prime source for initiating an Orphic / mythological movement in tribute to Chopin in the 1850s, which involved his friends (Clésinger, Kwiatkowski, Delacroix, Liszt, Berlioz, Viardot).  Grossly exaggerating, Arthur Hedley postulates that Jane Stirling "devoted herself to the cult of his memory".¹

This after-construction is reflected later in publications by other writers (e.g. Tad Szulc, Chopin in Paris, 1998;  Marie-Paule Rambeau, Chopin: L'enchanteur autoritaire, 2005;ª  John Rink and Jim Samson, Chopin Studies 2, Vol. 2, 2006).  A portrait of Jane Stirling as a young woman has provided a misleading impression.

In reality:

The Scottish sisters found an inexpensive apartment in London for Chopin in April 1848.  Then the sisters became convenient, well-meaning and possibly paid intermediaries for Jenny Lind, who had arrived in London at the same time.

That is:  they were a cover for Jenny Lind's meetings with Chopin in London and Scotland, and participants in the project of collecting, annotating and publishing his manuscripts and in the handling of his estate. - Why have scholars been so adamant to hide Jenny Lind?