I think whatever mode you choose for e-strike becomes a base ability and is gained by Fractal Replication. That means, +2 and go again would also work.
The base power however is more complicated matter. We use the stage order here where multiple effects apply.
One important thing to note is that all effects apply to all objects in the arena at the given time. It doesn't matter that e-strike has been played earlier than Fractal Replication.
~~So, at stage 1 Fractal gets all copyable properties and its power is set to 0 because there are no other illusionist attack action cards yet. It is stage 5 when e-strike becomes illusionist, stage 6 when abilities like phantasm and on-attack draw (or the other two modes of e-strike) are applied and stage 7 when the base power of e-strike is set to 8.
In your scenario Fractal Replication would be 0 power, with card draw and no go again.~~
Edit:
Thanks again for the question and the pleasant afternoon. We went from stage 1 to no stage and I have learned that * setting the base power is (as it should be, I guess) stage 7, after e-strike has become illusionist.
So 8 power is correct. @granite robin
Thanks all for your contribution 🙂