I think it's been more time since i unretired, but i'm not sure if i can check that ?
Regarding the "Lair" dfhack thing, i'm not aware of it.
AFAIK the features i use are autobutcher and workflow
according to legends viewer
In 128, early winter, The Diamond Mirror of The Sack of Ink launched an expedition to reclaim Lancebeach.
In 129, midspring, The Diamond Mirror of The Sack of Ink launched an expedition to reclaim Lancebeach.
In 129, early autumn, the dwarf Datan Whipflag created a masterful (UNKNOWN) for The Diamond Mirror at Lancebeach.
edit 2 : digging into the legends xml to try to get more precision on the reclaim dates
<historical_event>
<id>34056</id>
<year>128</year>
<seconds72>332557</seconds72>
<type>reclaim site</type>
<civ_id>68</civ_id>
<site_civ_id>456</site_civ_id>
<site_id>404</site_id>
<unretire/>
</historical_event>
<historical_event>
<id>34123</id>
<year>129</year>
<seconds72>54568</seconds72>
<type>reclaim site</type>
<civ_id>68</civ_id>
<site_civ_id>456</site_civ_id>
<site_id>404</site_id>
<unretire/>
</historical_event>
the crash time is a bit after the retre event (that's me restoring the save to go to legends mode)
<historical_event>
<id>34258</id>
<year>129</year>
<seconds72>213043</seconds72>
<type>site retired</type>
<civ_id>68</civ_id>
<site_civ_id>456</site_civ_id>
<site_id>404</site_id>
</historical_event>
I have no idea how to translate the "seconds72" to a date though
The crash happens at 10th Limestone
edit 3 : according to
http://dwarffortresswiki.org/index.php/v0.31:XML_dump, a year is 12 months of 28 days and is also 403200 seconds , meaning 1200 seconds per day.
THat would put my unretire at 18 slate, roughly 4.5 months before the crash