5 Bb5 this already a clear advantage for white. See Horwitz Harrawitz 1846!
There is some good analysis in Dave's book on Ponziani
Yes, I've seen that game. 7.Ne5! looks like a dangerous improvement on that game, but Black seems to be ok after the Schliemann-esque 5...Qd6!?
You are right Dave 4.ef5 is very strong and after 4... e4 we are playing Nd4 and d3. Almost a clear advantage for white
What does White play on 4...d5?