How wonderful to find someone who is also looking for some of these people.
The earliest that I have found Ebenezer is on a 1789 list of landowners of the Lunenburg District (later Eastern still later Johnstown District).An 1803 report of the Heir and Devisee Commission (sorted out Upper Canada land titles) confirms George Allen (carpenter from USA) as the owner of the N1/2 of lot 28 concession 2 Elizabethtown whose original owner was Ebenenzer.So I believe that Ebenezer would have been an adult in 1784 when the loyalists were getting their land grants.
In 1799, he was granted a lot in Wolford Twp which he sold in 1805.In that record, he was listed as being 'yeoman of Haldimand Twp'.
Unfortunately, the only child that I have listed for him is Weston Ebenezer b 1814 in Haldimand.
George and his wife Sarah Cole certainly had a son named Ira b1802? (and a dau Permelia b1804-7?) but so might Ebenezer have had since it seems to have been a family name: their bro Henry (wife Phebe) also had a son Ira b 1802?
I have run across Justus in in the early land petitions (1795) but have no idea if he is related.