I don’t understand why there is any lack of clarity on this simple subject. The UK owes our regular contributions up to the date of departure. The UK owes no contributions thereafter or special payments to leave.
If they want us to stay in the EIB we can come to an agreement about our capital in that Bank. If we want to stay in Erasmus and they want us in there will be a continuing payment related to our share of Erasmus spending as a non EU member of it. Our paid up capital in the ECB is small and not a major issue. If they want us to keep our small shareholding we could.