Tokyo Haneda to Hakuba best way?

Greetings, my friends and I would like your advice please. We arrive at Tokyo Haneda approx 5.30 am on the 19th Feb. We wish to bullet train it as close as possible to Hakuba, returning a week later. Then explore via train say for 2 out 4-5 days. Question - we think the JR East pass is the way to go - but understand a bus is required for the last leg, or a local train? Please advise cost / where we buy / can we reserve the bullet train on the morning of the 19th / do we need to / what is the Green version of the pass / and what station do we need to get to from Haneda in order to connect with the Nagano bullet train?

Thanks large!

a bus is required for the last leg, or a local train?
--- A bus, by the Alpico bus:
https://www.alpico.co.jp/access/express/nagano_hakuba/

Please advise cost
--- It starts from 1,800 yen for Hakuba-Goryu.
https://www.alpico.co.jp/access/express/nagano_hakuba/#fare_table

where we buy
--- At the east exit of Nagano Station, "科の木東口" between the yellow 22 and 25 in this figure:
https://www.alpico.co.jp/access/station/nagano_sta.html

can we reserve the bullet train on the morning of the 19th
--- Yes, through the "JR-EAST Train Reservation" on this site:
http://www.jreast.co.jp/e/

do we need to
--- If you want to sit on a reserved car.

what is the Green version of the pass
--- With it, you could reserve a seat on a Green car (2-2 seats, while non-Green 2-3 seats)

what station do we need to get to from Haneda in order to connect with the Nagano bullet train?
--- At Haneda, get on a Tokyo Monorail (valid by a JR East Pass) to its terminal "Hamamatsucho" station. Then, move on to a transfer gate to take either a JR Yamanote (green) / a Keihintohoku (cyan) line to "Tokyo" station, where a bullet train departs.
https://www.google.com/maps/dir/Haneda+International/Tokyo+Station/
http://www.japan-guide.com/e/e2361_02.html