Todd

Todd
Common Ground (3×07), The Seer (4×08), Miller’s Crossing (4×09),
Be All My Sins Remember’d (4×11), Spoils of War (4×12), The Kindred, part I (4×18),
The Last Man (4×20), The Queen (5×08), First Contact (5×10), The Lost Tribe (5×11),
Infection (5×17), Vegas (5×19), Enemy At The Gate (5×20) –
Christopher Heyerdahl

Except in Be All My Sins Remember’d – voiced by Heyerdahl but played by Brendan Penny and possibly Spoils Of War because there is conflicting information about who played him in this episode.

Appearance in SGA: Legacy as Guide

Michael

Michael (name given on the show)
Michael (2×18), Allies (2×20),
No Man’s Land (3×01), Misbegotten (3×02),
Vengeance (3×19), The Kindred, part I (4×18), The Kindred, part II (4×19), The Last Man (4×20) Search & Rescue (5×01), Prodigal (5×14) –
Connor Trinneer Except in Allies – voiced by Trinneer but played by Brent Stait and in his Wraith form played by James Lafazanos (not confirmed)

Mentioned in SGA:Legacy as Lastlight

Here are the human form and the Wraith form of Michael.

Bullseye

Bullseye
First Contact (5×10)/The Lost Tribe (5×11)(speculation) –
actor is a bit of a mystery.

GateWorld Episodes and Stargate Wiki conflict on who was in First Contact. Stargate Wiki says James Chutter as “Billy”, Brendan Penny as Wraith. But GateWorld doesn’t list Brendan Penny amongst the episode guest stars. Meanwhile the IMDb page for Brendan Penny doesn’t say he was in First Contact either. James Chutter is a male Wraith in The Lost Tribe and WDC members agreed that this photo is his character.