Does his interrupt to make an attack mean that He interrupts the timing sequence for who does what first in the end of round sequence, so regardless of initiative He gets too attack first.

This was discussed in another thread, and as I recall the consensus was that the "interrupt" in the text doesn't change anything timing wise. There were dissenting opinions, but I don't know if the question went off to FFG.

Each ability specifies a timing trigger for the ability -- either explicitly or implicitly (due to "during an activation" or "during an attack"/"while attacking"/"while defending"). The word interrupt has no attached meaning that would change timings of abilities.