Kobe Maya Mountain Hiking

I am planning to climb Kobe Mt. Maya in mid June early in the morning around 6 am. I will be staying in Oriental Hotel, which is 5-10 min away from Shin-Kobe station by car. I'm trying to estimate the time required to reach the mountain top starting from Shin-Kobe ropeway station based on the information given by this site.

1. Shin-Kobe ropeway station to Nunobiki waterfall (15-20 min)
2. Nunobiki waterfall to Nunobiki Herb Garden low entrance (20-25 min)
3. Nunoboki Herb Garden low entrance to Observation Deck (30 min)

So that's around 1 hour (if taking slower pace, could be easily 1.5 hours). According to the japan-guide.com's post, from the Observation Deck the same trail continues on Mt. Maya and I couldn't understand this part. Question goes:

1. Does this mean Observation Deck is not the mountain peak?
2. How long would I have to climb more to reach the mountain top?
3. Will Observation Deck be good enough to see Kobe city's view? I won't have enough time in the morning so if this place presents nice panorama, I'll climb down from here.
4. Supposing I go up till Observation Deck and return, including half an hour of landscape viewing, would 3 hours be enough?

Thank you.

http://www.feel-kobe.jp/kobe-yakei/area/mountain/
https://www.google.com/maps/d/viewer?mid=zfAc7ggjkyrU.kTMWrCmP4Ydg&msa...

the map on the above website.
Nunobiki Herb garden is [No.2].
Mt.Maya is [No.3]
Mt.Kobe is [No.5]

Thank you for the reply.

How long would it take to reach No.3 (Mt. Maya) by walking?
Also, I'm planning to go there in early morning so Nunobiki Herb Garden won't be open. Can I still enter the Observatory?