If there would have been no contact if the boat ahead did not bear away, didn't the boat behind initially keep clear?
I would answer no. To be able to pass at 5 millimeter astern of a ROW boat is not keeping clear from the (b) part definition of what is to keep clear :
(b) when the boats are overlapped, if the right-of-way boat can also change course in both directions without immediately making contact.
Just before the contact, the boats were overlapped. Remind also that the course change of the heading boat was as little as 5° so it is clear imo that the contact was immediat and consequently the behind boat was not keeping clear even if no contact.
2. By bearing away, did the boat ahead give the boat behind room to keep clear?
This question can be rejected because as said above the behind boat already didnt keep clear. To have room to keep clear means that initially you had a keeping-clear course .
All that interressant questions led me to change my mind about the rule which was violated. Now I would say it was a 11 violation.
JL