I will also wish everyone good luck! This is the last chance for me or anyone in my position (2nd year who applied last year) to apply so hopefully I made it count!
I unfortunately can't help with this fork in the road, but have a question myself about the EAPSI. Would it looked negatively upon to apply with a collaboration with an individual with which you have worked with in the past? IE the institute would be part of a more ongoing collaboration. I haven't found any information in the application instructions that suggests it would be worse or better to do this.