Improving the rolls PCs cannot Aid each other on either the +Fortunes roll or on rolls to generate Surplus. The move assumes that everyone is doing their part already.
PCs can Bolster for a coming season and spend the Preparation on the roll(s), but doing so should requiring a significant sacrifice to the gods (like 1 Surplus at least), and/or having the village Pull Together to make special preparations.
Handle other moves on a case-by-case basis, based on the fiction and what the whole group feels is right and fair.
Box
SEASONS CHANGE
When spring bursts forth upon the land , whoever is the most
hopeful rolls +Fortunes: on a 10+ , pick 1 seasonal gain; on a 7-9 , pick 1 seasonal gain, but a threat to the steading makes itself known or gets worse; on a 6- , threats abound (and don't mark XP).
Whatever the result, reset Fortunes to +1.
When the hot days of summer settle across the land , whoever is most content rolls +Fortunes:
on a 10+ , pick 2 seasonal gains; on a 7-9 , pick 1 seasonal gain; on a 6- , a threat to the steading makes itself known or gets worse (and don't mark XP).
Whatever the result, the steading generates 1d4-1 Surplus. Then, reset Fortunes to +1.
When autumn falls and the land is ripe for harvest , whoever is most determined rolls
+Fortunes: on a 10+ , pick 1 seasonal gain; on a 7-9 , pick 1 seasonal gain, but a threat to the steading makes itself known or gets worse; on a 6 -, threats abound (and don't mark XP).
Whatever the result, reset Fortunes to +1.
When the harvest is complete , roll 1d4; the steading generates that much Surplus.
When winter grips the land , whoever is weariest rolls
1d4+Population (min 0); the steading consumes that much Surplus. If there's not enough, reduce Surplus to 0, reduce Fortunes by 1, and pick 1:
Reduce Population by 1 (min -1) due to death, decripitude, and departure
An important resource (one of the horses, the cistern, etc.) is lost or not maintained
An important NPC dies, their role unfilled
Your PC dies, leaves, or retires from play
Then, roll +Fortunes: on a 10+ , the winter is relatively mild, and each player can name a local NPC with whom their relationship improves at least a little (work together to figure out how); on a 7-9 , the steading must consume additional Surplus equal to 1d4+Population before winter ends or suffer the consequences as above; on a 6- , as a 7-9, but also threats abound (and don't mark XP).
Whatever the result, reset Fortunes to +1.