Late july osaka-kyoto-tokyo

Hi, i'm planning a 1st time trip to japan with plans to visit osaka kyoto and tokyo for 7 nights.

I have already bought the airfare which is from july 23 (1030pm arrive at haneda) to july 31(1145pm departure at haneda)
my planned itinerary is as follows:

23 july-tokyo(haneda)
24 tokyo-osaka(via bullet train)
24-27 osaka-kyoto
28 osaka-tokyo(bullet train)
28-31 tokyo

What is the question?

Sorry the questions are

Is getting the jrpass necessary, I like to prioritise the time, getting the most out of it in these 3 places.

Is it feasible for staying in Osaka for 4 nights and then spending 3.5 nights in Tokyo later on. I plan to go Kyoto for day trip only

For the first night since the arrival time at haneda is almost midnight. What are the best options to get to Osaka the next day

And lastly i like to have some suggestions as to what I can do for my itinerary. My plan currently is just allocating 1 day at Tokyo mainly for Disneyland, not intending to visit uss in Osaka, thanks

A JR Pass would provide some savings over regular tickts, but there are other options which would probably be even cheaper. If you really want to take the Shinkansen, the cheapest option would be the Platt Kodama tickets, but they require that you take the slower Kodama trains. Alternatively, the Tokyo-Osaka round trip package from Japanican is slightly more expensive but allows you to take the faster Nozomi trains, which is not possible with a JR Pass.

http://www.jrtours.co.jp/kodama/en/
http://www.japanican.com/en/tour/detail/VJOPENTO1/?GN_tours

If you are willing to consider flying, flights by low-cost airlines Peach or Jetstar (between Narita and Kansai airports) or by (almost) regular airline Skymark (between Haneda and Kobe airports) will probably be the cheapest even if you count transportation to/from airports.

4 days in Osaka and 3 days in Tokyo is certainly feasible.

The cheapest accomodation near Haneda airport are the many business hotels located around Kamata station, which can be booked on standard booking websites like booking.com or Rakuten. From Kamata station you can go to Shinagawa and take a Shinkansen, or go back to Haneda if you decide to fly, it's about 15 minutes either way.

Thanks, first thing I want to nail down is the transportation.

I plan to get the JRpass as it would cover the cost of just for a round trip of tokyo-osaka via shinkansen and I also like to have a first hand experience riding in one.

Is it advisable to sleep at the airport after arrival since it's almost midnight or should I find a hotel at around Kamata station?

I have read on the net that most JRpass offices don't operate till late night, so the earliest I can get the JRpass to get to Osaka is at Shinagawa station which opens at 9am right?

Staying overnight at Haneda is possible, whether you should do it is up to you, but if you are worried about safety aspects, this is Japan. You can look at the airport's website to see what services are available.

The exchange office at Shinagawa indeed opens at 9am, but it is not the earluest. The ones at Tokyo station and at Haneda open at 7:30 and 7:45 respectively.