I am interested to know where Erwin, brother of Frederick is when the 1841 census was taken. The only Erwin I have found is Erwin son of Frederick, also who and when did he marry and his children. Did he stay in England or did he immigrate somewhere.
Burg, what (if any) info do you have about the fate of Erwin Burgoyne, son of Frederick and Elizabeth (and elder brother of your Frederick William)?
I am wondering whether you are aware of him having joined the Royal Navy. You have probably long since spotted this, but Anc***ry.com have filmed the RN medal rolls for the Crimean campaign and those record an Erwin Burgoyne serving as an ordinary seaman in HMS St Jean d'Acre: TNA ref. ADM 171/28 fo.63r.
He also received a campaign medal for service in the Baltic with the same vessel, 1854-55: ADM 171/19 fo.102r. That roll includes the comment that the medal was delivered to him later -- 13/8/57, by which date he was apparently one of the ship's company of HMS Indus.
If this is not your man, I suppose it could just as easily be the son of William and Grace Burgoyne (b.1835 per your Reply 52 above). I would think that William and Dorothy's mystery Erwin b.1816 would have been a bit long in the tooth by the 1850s, but absent more evidence I suppose he too should not be totally excluded as a possibility. The difficulty of finding adult refs. to the latter, plus the infant mortality rate of the time, rather suggest that Plymouth burial registers before circa 1830 may be the place to catch him.
As I say, the medal info is likely to be old news to you. But always safest to check . . .
Rol