Connor
Hello,
Unfortunately it is not possible for the support team or developers to change the league rules after the season has started.
However, for tyre rules, this can be managed manually by clearly advertising the rule on the league wall and then having the host (or somebody else from the league) check everyone's tyres at the end of the race. Without the rule enabled in-game, managers won't be disqualified for not using two compounds, however the host can create their own punishments accordingly*.
No refuelling is a little harder to check manually, but if you ask your league members to adhere to the no-refuelling rule, any people who don't will be quite easily identifiable as they will be much quicker in the first stint (due to their lack of fuel in relation to everybody else).
The point for Fastest lap can be calculated by the league host and added onto the standings separately, however it won't count officially on the in-game standings.
Sorry for any inconvenience this may cause.
*Some leagues choose to use a punishments of "the manager must start on Hard tyres" or "must stop on the first lap" for disobeying the tyre rules.
Hello,
Since writing this, I have been in contact with Kevin Bissell who has intelligently informed me that what I wrote about enforcing a no-refuelling rule in a league where refuelling is enabled will only work if
all of the league's managers are active in the race live as there is no other trigger to get cars to pit. Without being in the race and manually pitting your drivers, they will not stop for new tyres which will more than likely lead to the tyres puncturing as they won't be changed in the race.
Any teams who don't save a setup will be on the default Medium strategy and will automatically be on lower fuel loads as they will be running the race with refuelling enabled (as that is what the league rules are set as), so it is important that as well as everyone being live in the viewer, they all have to have saved a strategy.