I don’t think it’s likely that Barret is Henry’s dad since they’ve already filmed the episode he’s revealed in and have only just started looking for this role.
Could possible be Baelfire – I’m going to link to another discussion page for this, just because I don’t think we’re allowed to discuss it openly here – casting etc. for future episodes being spoilers. But definitely share this idea with us on this thread:
https://oncepodcast.com/forums/viewtopic.php?f=81&t=1571
Then we won’t have to worry about spoiling for others.
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