Need help regarding my itinerary South Island

Hi,

Previously I had this itinerary for my mid of May travel starting from 11th May 26, but now I have extended my tickets and I have 2 more nights to explore south Island. I want to visit Milford, Hooker Valley, Greymouth Train Trip & Fox Glacier.

Previous Itinerary:

Day 1: Night arrival ZQN

Day 2: Explore ZQN and stay ZQN

Day 3: to Mt Cook & stay Mt cook (Heli Tour + Hooker)

Day 4: Stay Twizel ( Sealy Tarns & Lake Tekapo)

Day 5: to Te Anau via Wanaka & stay Te Anau

Day 6: Milford & stay Te Anau

Day 7: to ZQN & stay ZQN

Day 8: fly out from ZQN

Now as I have added 2 more nights, so now:

Day 1: Night arrival ZQN

Day 2: Explore ZQN and stay ZQN

Day 3: to Franz Joseph/fox Glacier via blue pool & stay Franz Joseph/fox village

Day 4: Heli & Glacier explore & stay there

Day 5: to Hokitika Gorge & stay there

Day 6: Catch train from Greymouth to CHC & stay CHC

Day 7: explore CHC and evening flight CHC to ZQN, stay ZQN.

Day 8: Coach to Milford and Stay ZQN

Day 9: rest and explore city stay ZQN (Visit Arrowtown, Glenorchy)

Day 10: fly ZQN to Sydney

or if travel by road then:

Day 7: to Mt Cook/Twizel via Lake Tekapo & stay there

Day 8: visit Hooker Valley & head to Wanaka

Day 9: Visit Lakes, waterfall in Wanaka & head to ZQN

Day 10: fly back to Australia from ZQN

OR:

Day 1: ZQN

Day 2: Coach to Milford - Stay ZQN

Day 3: explore, rest and stay ZQN

Day 4: Drive to Mt Cook via , stay Mt Cook

Day 5: Hooker Track & drive to CHC via Lake Tekapo

Day 6: rest, explore, stay CHC

Day 7: Train to Greymouth (arrival 1:15PM),?? pls suggest where to stay here?

Day 8: explore glacier via heli, and stay fox glacier pls suggest what else to visit around here??

Day 9: Drive to ZQN, stay ZQN

Day 10: Catch Night Flight

Please suggest:

1- What is the most reasonable, and appropriate itinerary that I should rely upon to experience Franz Joseph, Train to CHC, Milford and hooker valley.

2- Should I visit both Franz Joseph and Mt Cook or one of them? which one is more worth visiting and staying?

3- Which is better to stay Franz Joseph or Fox Glacier?

4- Will FWD/2WD (such as Cherry Tiggo 4 Ultimo/Toyotal Corolla Hatchback) be enough for this mid of May trip?

5- is it a must to carry chains in my car all the time or only before Milford should I hire from somewhere??