Hi Mike,
well done on your finds.
Being something of a Francophile I've been scouring the net and then atlases for Breident, alleged birthplace of Alfred Jr's wife Pauline Montagu, but no luck.

Another look at LDS gave this, just one year after Alfred became Rector at Blaisdon;

England and Wales Census, 1891
Name: Pauline Edersheim
Event Type: Census
Event Date: 1891
Gender: Female
Age: 34
Relationship to Head of Household: Wife
Birthplace: Boulogne #
Schedule Type: Household
Registration District: Westbury On Severn
Sub-District: Huntley
Ecclesiastical Parish: Blaisdon
Parish: Blaisdon
County: Gloucestershire

Name: Alfred Edersheim
Event Type: Census
Event Date: 1891
Gender: Male
Age: 35
Relationship to Head of Household: Head
Birthplace: Aberdeen
Schedule Type: Household
Registration District: Westbury On Severn
Sub-District: Huntley
Ecclesiastical Parish: Blaisdon
Parish: Blaisdon
County: Gloucestershire

Name: Dorothy Edersheim
Event Type: Census
Event Date: 1891
Gender: Female
Age: 6
Relationship to Head of Household: Daughter
Birthplace: Bridport, Dorsetshire
Schedule Type: Household
Registration District: Westbury On Severn
Sub-District: Huntley
Ecclesiastical Parish: Blaisdon
Parish: Blaisdon
County: Gloucestershire

# Not far from Boulogne, just inland of neighbouring Le Touquet, is the small village of Brexent-Enocq, population about 360 in the 1860s, not much bigger now. Is this "Breident" I wonder, I can quite understand it being mispelt !

So Dorothy was born (and Christened Dorothy Julia) in Bridport, Dorset around New Year 1885, while Alfred was Curate at Huntley, perhaps they'd been visiting Alfred's parents for Christmas ?.
[I met my wife at Weymouth, very near Bridport... some years later I tried to persuade her to "hurry it up" while visiting my parents in Cinderford over Christmas 1996, but "sadly" our son was born a vurriner at our Middlesex "home" a week later... this is getting spooky].

Sadly Dorothy died when just a child, in Somerset. How sad for her mother, only 18 months year after father Alfred Jr had supposedly eloped !

Name: Dorothy Edersheim
Event Type: Death
Registration Quarter: Jul-Aug-Sep
Registration Year: 1897
Registration District: Keynsham
County: Somerset
Event Place: Keynsham, Somerset, England
Age (available after 1866): 12
Birth Year (Estimated): 1885
Volume: 5C
Page: 363
Line Number: 231

According to LDS, which may well be wrong, Alfred 3rd wasn't in the Huntley household for the 1891 Census. ?? This seems odd as he was also born in Bridport and only 18 months after Dorothy.

Name: Alfred Montagu Edersheim
Event Type: Birth Registration
Registration Quarter: Oct-Nov-Dec
Registration Year: 1886
Registration District: Bridport
County: Dorset
Event Place: Bridport, Dorset, England
Mother's Maiden Name (not available before 1911 Q3):
Volume: 5A
Page: 367
Line Number: 319

I cannot find any sign of Alfred 3rd on LDS after this.

I think he was born in Bridport, rather than Huntley, as by now his father Alfred Jr had finished working at Huntley and was in Suffolk, presumably mother Pauline stayed with her inlaws. According to Alfred Jr's aforementioned biography he didn't appear to travel to France for work. Perhaps still thinking about when I met my wife nr Bridport, I HAD "decided" that Alfred Jr met pretty Mam'selle Pauline Montague at his hometown of Bridport, while she was visiting, or had moved there to find work, it being less than a day's sailing from Boulogne, perhaps she was from a fishing family ??. Afterall, Bridport has a 750 year history of rope and net making, the nets for the 1966 World Cup Final and all the Wimbledon LTA Championships are made at Bridport...

However once again my guess is very poor, clearly Alfred moved in much higher circles than I imagined, perhaps that's why the marriage ultimately failed ?;

"England and Wales Census, 1881"
Name: Lydia D P Montigue
Age (Original): 25
Gender: Female
Birth Year: 1856
Birthplace: France
Relationship to Head of Household: Sister
Marital Status: Single
Occupation:
Address: Cambridge Villas Cambridge Road
Event Place: Aldershot (Hants), Surrey, England
Disability:
Record Type: Household
GS Film number: 1341183
Affiliate Publication Number: RG11
Piece/Folio: 781 / 10
Page Number: 13
Household Gender Age Birthplace
Head Phillip Montigue M 29 France
Wife Evelyn M Montigue F 20 Liverpool, Lancashire, England
Sister Lydia D P Montigue F 25 France
Servant John Bradbury M 38 Birmingham, Warwickshire, England
Servant Ann Bradbury F 33 Ireland
Daughter Zoe Montague (Bradbury) F 4 London, Middlesex, England

"England and Wales Census, 1871"
Name: Laura J P Montague
Event Type: Census
Event Date: 1871
Gender: Female
Age: 16
Relationship to Head of Household: Daughter
Birthplace: France
Schedule Type: Household
Registration District: St George Hanover Square
Sub-District:
Parish: St George Hanover Sq
County: London, Middlesex
Household Gender Age Birthplace
Self John M P Montague M 47 Chelsea, Middlesex
Son Philip Montague M 20 France
Daughter Laura J P Montague F 16 France
Daughter Emily C E A Montague F 8 Madpole, Dorsetshire
Sister Eliza Derbishire F 42 Chelsea, Middlesex
Sister Susanna Derbishire F 38 Chelsea, Middlesex
Servant James Foley M 55 Maymoath, Ireland
Servant Harrit Chessex F 32 Vaud, Switzerland
Servant Hannah T Colman F 28 Handsworth, Norfolk
Servant Phobe Ward F 23 Bridport, Dorsetshire
Servant Mathew Conton M 15 Bridport, Dorsetshire

Which links nicely his Bridport roots, their Hanover Sq London marriage and the 1927 Probate details of her living her latter days at Fleet, Hants.

BUT come on Mike, over to you for the final chapter; WHERE did Alfred Junior go....and WHO was the local Squire's daughter ??
As you say, I like a good mystery....