So, something I decided to do is list all characters alphabetically listing each of their debuts in each series. So, here we go.
A-I
| Character | SFS | JAFAGU | SFSF | IFATW |
|---|---|---|---|---|
| Dodge | 01.03.Saving Benjamin | N/A | 05.17.Splodge Off Sodor | N/A |
| Donald and Douglas | 01.01.Emily to the Rescue | N/A | 01.01.Duck's Special Job (cameo) 04.10.Gordon and the Scottish Twins (first speaking role) |
18.14.Scots In Ireland |
| Duchess | N/A | 05.17.Splodge Off Sodor | 18.09.Duchess | |
| Duck | 01.01.Emily to the Rescue (cameo) 01.02.Memories (first speaking role) |
01.01.Jacob's New Job | 01.01.Duck's Special Job | 01.01.Untitled Duck, Chloe, Dennis, and Chinansa Episode |
| Edward | 01.01.Emily to the Rescue (cameo) 01.02.Memories (first speaking role) |
01.05.Old Edward | 02.06.A Gemmy Christmas | 13.02.Jacob Back In China (mentioned) |
| Gordon | 01.01.Emily to the Rescue | 02.01.Sierra Comes Home (cameo) | 02.06.A Gemmy Christmas | 03.06.The Great Race? |
| Henry | 01.01.Emily to the Rescue | 01.06.Saved From Scrap | 02.06.A Gemmy Christmas (cameo) 04.02.Henry and Spencer (first speaking role) |
08.12.The God of Death |
J-R
| Character | SFS | JAFAGU | SFSF | IFATW |
|---|---|---|---|---|
| James | 01.01.Emily to the Rescue | N/A | 02.06.A Gemmy Christmas (cameo) 04.01.Toby and James (first speaking role) |
04.02.Untitled James and Analise Episode |
| Oliver the Engine | 01.01.Emily to the Rescue | N/A | 01.01.Duck's Special Job (cameo) 04.03.Oliver and Percy (first speaking role) |
N/A |
| Percy | 01.01.Emily to the Rescue | 01.06.Saved From Scrap (cameo) | 02.06.A Gemmy Christmas | 19.07.A Visit from Percy |
S-Z
| Character | SFS | JAFAGU | SFSF | IFATW |
|---|---|---|---|---|
| Splatter | 01.03.Saving Benjamin | N/A | 05.17.Splodge Off Sodor | N/A |
| Thomas | 01.01.Emily to the Rescue (cameo) 01.02.Memories (first speaking role) |
01.06.Saved From Scrap (cameo) | 01.04.Story Time Part 1 (mentioned) 04.17.Thomas, Percy, and Duck (first speaking role) |
18.13.Thomas and Saoirse |
| Toby | 01.01.Emily to the Rescue (cameo) 01.02.Memories (first speaking role) |
N/A | 04.01.Toby and James | 04.14.Axel and Toby |