As far as I can tell, the factors you mention refer to the possibility of influencing astronomically valuable worlds. I agree locking in some properties of the world may be possible. However, even in this case, I would expect the interventions causing the lock-in to increase the probability of astronomically valuable worlds by an astronomically small amount. I think the counterfactual interventions would cause a similarly valuable lock-in slightly later, and that the difference between the factual and counterfactual expected impartial welfare would quickly tend to 0 over time, such that is is negligible after 100 years or so.
As far as I can tell, the factors you mention refer to the possibility of influencing astronomically valuable worlds. I agree locking in some properties of the world may be possible. However, even in this case, I would expect the interventions causing the lock-in to increase the probability of astronomically valuable worlds by an astronomically small amount. I think the counterfactual interventions would cause a similarly valuable lock-in slightly later, and that the difference between the factual and counterfactual expected impartial welfare would quickly tend to 0 over time, such that is is negligible after 100 years or so.