The Greyhide sexcapades can be a bit involved to trigger, and it has been bugged in the past. The first event you have to trigger is "drinking buddies":
Code:
./events/ruler_events_5.rpy: event('drinking_buddies', triggers="week_end", conditions=('week >=4',), active=False, group='ruler_event', run_count=1, priority=pr_ruler, weekend_auto=False, weekend_room="bg21")
What that all means is that the event is triggered when Rowan goes to the tavern ("bg21") where it will show as a button after week 4. So you can't even start until after you have a Tavern up and running and have built the forge, causing you to meet Greyhide. It's not marked as active, because it gets inserted into the event stack during the passage where Andras takes Rowan down to the newly refurbished forge for the first time to meet Greyhide.
During "drinking buddies" there's dialog options where Rowan can suggest whether Greyhide has ever considered men or whether he would like to meet his wife. In the past I think this was the way the followup events got into the queue, and there is indeed a "drinking_buddies_introduce_alexia" that gets set. However, I think this is just stale code since it doesn't get referenced anywhere else. There's also alternative narrative in there where Greyhide mentions meeting Alexia already in the Forge if Rowan had sent her down to work. Considering how late in the game that scenario happens, I wonder if anybody has actually seen that appear.
The next event "greyhide meets alexia" used to be triggered off of that selection, but now it just gets queued automatically after "drinking buddies" has finished:
Code:
./events/ruler_events_characters.rpy: event('greyhide_meets_alexia', triggers="week_end", depends=('drinking_buddies',), group='ruler_event', run_count=1, priority='pr_story')
This is a passage where Alexia meets Greyhide outside feeding birds. IIRC this is somewhat new since older releases had the events progress from "drinking buddies" straight to the next in sequence "Greyhide's Table Manners" unless my brain cells are letting me down.
Code:
./events/ruler_events_7.rpy: event('greyhide_s_table_manners', triggers="week_end", conditions=('week >=4',), depends=('drinking_buddies','greyhide_meets_alexia',), group='ruler_event', run_count=1, priority=pr_ruler, weekend_auto=False, weekend_room="bg22")
"bg22" is the forge where this event gets triggered by a button that appears after the other conditions are met.
This is the dinner scene that most people have seen when choosing to pursue the Greyhide story. Jezera gets wind of planned social and scurries off to secretly spike Greyhide's stash of FireGrout (implied). Rowan gets called away mid dinner so that things can be brought to a head so to speak. I think in previous versions, there might have been corruption level checks involved, but there are none in the current release. Allowing Alexia to "Ask the Question" and then "Touch It" will allow things to develop and then be brought out into the open leaving a mess that will need to be dealt with.
Next in sequence is "Greyhide shares his people's liquor" which used to be triggered from "drinking buddies" if Rowan asks Greyhide if he has considered male companionship. The comments for the event even still document that this way but as you see from the rule, it only relies on "Greyhide's Table Manners" finishing.
Code:
./events/ruler_events_11.rpy: event('greyhide_shares_his_people_s_liquor', triggers="week_end", depends=('greyhide_s_table_manners',), group='ruler_event', run_count=1, priority=pr_ruler, weekend_auto=False, weekend_room="bg22")
Event shows as a button in the forge ("bg22") one or more weeks after "Table Manners".
Rowan goes down to the forge for another round of drinking with Greyhide, so this time Greyhide breaks out his famously spiked FireGrout to reply in kind to the Rosarian wine offered in "drinking buddies". Sexy times ensues if you choose the Kiss option during the narrative.
The next event is the threeway but it is gated behind what I believe to be an absurd set of maximum corruption checks on Alexia and Rowan (both must be less than 20). It will only trigger after Raeve Keep has fallen:
Code:
event('after_drinking_greyhides_alchol', triggers="week_end",
conditions=('NTR', 'ev_happened("greyhide_shares_his_people_s_liquor")', 'avatar.corruption < 20', 'all_actors["alexia"].corruption < 20'),
depends=('raeve_keep_visit_goal2',), group='ruler_event', run_count=1, priority=pr_ruler, weekend_auto=False, weekend_room="bg22")
I've bitched about the absurdity of this in the past. Why do you both have to stay relatively moral to trigger the threeway? Back then the devs here mumbled something about the whole thing being in the process of being rewritten, but here we still are. The only justification I can think of is that the scene involves Jezera calling the couple to her room for a proper sex shaming of either or both of them for their transgessions while spiking their tea with some more of the wacky torpedo juice. Greyhide also shows up for the "dressing down", and the threesome will only happen if the couple pursues Greyhide back to the forge after he storms out.
If you want to bypass the corruption checks, I've hacked them out of the attached ruler_events_16.rpy file. Park this in your game/events folder. You may need to create the events subfolder if you haven't previously unpacked the rpa archives. I'm not sure if the event mechanism is dynamic to the point where you can do this and start SOC and load a game from on or before the "Grayhide shares his people's liquor" is run. Otherwise you can definitely start with a new playthrough. You can also probably trigger it by hand after that event happens by jumping into the console, verifying that Rowan and/or Alexia have been too corrupted:
Code:
avatar.corruption
(returns more than 20?)
change_base_stat('c',-x)
(where x is however much you need to subtract to get it below 20)
all_actors['alexia'].corruption
(more than 20?)
change_corruption_actor('alexia',-x)
(where x is the amount to subtract)
I mean, you can pretty much change all the variables with the console, though there's always a chance that will mess things up. If you're asking if that would unlock Greyhide/Alexia scenes, I have no clue the requirements for the Greyhide/Alexia scenes but have always assumed they were triggered by Rowan's choices when getting drunk with Greyhide and at the dinner with all three, which would be done with True/False variables, not numbers.
If so, it is...possible to change those, but often a bad idea with the console in this game. It's very possible you miss some variables and make scenes impossible to proc unless you go back in and fix things.
TLDR: Editing variables is easy, but editing True/False stuff can go badly. It's generally best to stick to changing number variables unless you're willing to put in a lot of legwork.