Hokkaido self drive September

Hi
We will visit Hokkaido on 19-26 September 2015 and plan to drive around.
There are 10 adults and we will rent 2 cars.
This is our first trip and would appreciate it someone can comment and/or advice on our itinerary.

D1 - Arrive Chitose Airport 12pm - drive to asahikawa + biei (stay at biei)
D2 - Biei + Furano
D3 - Furano to Noboribetsu
D4 - Noboribetsu + Lake Toya
D5 - Drive back to Sapporo
D6 - Otaru + Yoichi + Cape Kamui
D7 - Sapporo
D8 - Fly back to Singapore

Question:
1. Is Asahikawa Zoo worth visiting? Currently we dont plan to visit the zoo.
2. Which place is notable to visit in September?
3. ANother option is to visit Hakodate area.

Thanks!

Not even a full day at Lake Toya might be too rushed.
Consider staying a night there.

The zoo is probably one of Japan's best zoos. It's really nice.
But only if you're interested in zoos, I'd go there.
I only went because the weather was horrible and the zoo was pretty much the only thing I could do.

1. Singapore zoo is better than Asahikawa zoo
2. September is inbetween seasons and have no special place. However, you will encounter harvested fruits/vegetables. Fresh and yummy. See a grilled corn? Get it. See a raw corn? Grab it!!
3. Hakodate is a nice place for night/morning.

Additionally, I am not certain why you are spending so much time in Furano. It is past the lavender season. Biei is nice though.

OP is staying the night there. No?

Doing Lake Toya does not take much time. You can drive about the lake. Visit the local area. Walk about the town. Eat and hot spring. All this will take less than 4 hours.

Thanks for the comments and suggestions.
So we have decided to change our plans to:

D1 - Arrive Chitose Airport 12pm - Take JR to Hakodate and stay for the night.
D2 - Hakodate in the morning n afternoon then take JR to Noboribetsu and stay for the night (onsen).
D3 - Noboribetsu (lake Toya) to Sapporo by JR.
D4 - Sapporo to Asahikawa + Biei (driving) - back to Sapporo
D5 - Sapporo to Daizetsuzan + Furano - back to Sapporo
D6 - Otaru + Yoichi + Cape Kamui
D7 - Sapporo
D8 - Fly back to Singapore

Questions:
1. Is this a better itinerary?
2. Any recommendation for place to stay in Noboribetsu?

Going to Daisetsuzan National Park is a very good idea as in average year your time of visit is autumn foliage season in that region. Since you are visiting Asahikawa, it is more direct to approach the Park from there instead of going back to Sapporo first and start from there. Use Sounkyo as your base and there is shuttle service to the 2 popular koyo destinations in the Park, namely Ginsendai and Daisetsu Kogen Onsen. It maybe possible to do it as a day trip from Asahikawa, but to be on the safe side plan on staying a night in Sounkyo as the side trip is highly popular and there will be queues for the shuttle. Sounkyo itself is worth a stay for an onsen experience and additional sightseeing around the twin falls of Ginga no Taki and Ryusei no Taki as well as the scenic ropeway ride up Mt. Kurodake. Obako is also worth a photo stop.
http://ramblingonmyhokkaido.blog112.fc2.com/blog-entry-77.html (Ginsendai)
http://ramblingonmyhokkaido.blog112.fc2.com/blog-entry-95.html (Daisetsu Kogen Onsen)

It is out of our budget but in Noboribetsu a friend who had stayed there highly recommends Bourou Noguchi Noboribetsu, although it is slightly further away from the town center.
http://www.bourou.com/en

Thank for the advice and suggestions William5.