2 of which were in the League Cup against Bristol Rovers. Soldado's goals in the Europa League early rounds were dismissed as against inferior opposition yet you are making a comparison with goals against a 3rd Division side?
Yes, Janssen needs goals and probably sooner than he should because the monkeys will be on his back far too early as they seem to be already clamouring crap from the peanut gallery. But give the guy a chance. No goals from Kane, Dele, Eriksen or Dembele yet this season I see.
1) Yes, he needs official goals. Against anyone, from anywhere. Off his a*se if necessary, but he needs goals. This is the reality of the situation that recent history has pushed upon any strikers that this club signs. Else, every miss will draw flashbacks from the crowd of the time Bobby missed a similar chance in a similar game. It might be unfair, but it is inevitable, and it has nothing to do with monkeys or galleries or whatever it is you referenced in your post.
2) I say this as someone who thought Bobby's early goals were crucially important, and as someone who earnestly believed he would come good right up until he left.
3) Batahuayi has goals and an assist. They came against Bristol Rovers (save for the assist - that came late in a PL game, I think), but that's still more of a record than Janssen's got so far. Ideally, that needs to be rectified over the course of the next couple of seasons - in an ideal world, one would compare Batahuayi and Janssen's records at the end of a significant period of time at Chelsea and Spurs respectively, and conclude that Janssen was indeed the wiser option. To bolster Janssen's case, however, requires him to score or assist - they all count, after all.
4) Eriksen, Alli, Kane and Dembele have scored in the PL and England more broadly in the past, though, so we know they can do it. Again, not trying to be cruel, but it's a fact that Janssen's had one season scoring in the Eredivisie, a notoriously weak league on par with the Championship at times - such an origin will inevitably raise doubts.
Janssen's been bright, he works hard, looks sharper than the lads around him and has a physicality and sense of grit that bodes well for his chances of not becoming another Bobby, and of proving to be the better acquisition between him and Batshuayi. But he needs to score.