John
I think the evidence points to Adrien being the only Boitel to to come to London, possibly as you say following Jeanne Eusebe here, and three surviving children to them, Mary, Daniel and Jeanne, they are the only three who appear to have reached adulthood according to the tesmoignage records, and this does match with the fact these are the only three who appear in local marriage records and can have families traced for them.
I don't believe Susanne Boutet is the elder daughter, the burial age for her is way out, and there is also another instance of the Boutet name near by at St Botolph Bishops Gate, William Boutet christened 6 March 1753 to Edward and Esther Boutet.
The one source for your Peter also looking at the image is clearly 'Boutet'
St John Wapping 1726 'Peter, son of Peter Boutet, weaver, and Susanne his wife East Smithfields.
The Boutets were a quite seperate Huguenot family, and the name would have been pronounced quite differently from Boitel, and in fact most of that couple's children were baptised in the French Church at The Artillery between 1716-1739 as Boutet, her maiden name down as Landon. So he can be ruled out as Adrian's brother.
Likewise I don't think Edward Bowtell and the Susanne bitten by a mad dog were in any way related. Bowtell seems to be a common name escpecially linked with that parish St Botolphs, entries dating right back to the earliest registers in the 1570's! The similarity with Boitel in pronunciation seems to be a coincidence.