If our flight is VERY early in morning and we decide to walk to the terminal, is that possible?
It is walkable, but not recommended. It is not close. Especially with all the current construction going on at LGA. Best is the shuttle (Free) or Uber which will probably cost you about $8.
No. You need to take the shuttle.
My understanding is that you can walk over the bridge. It is not very far. The hotel has a free shuttle also. You will want to check with hotel to make sure it runs early enough. Best of luck with your trip!
Eventhough you see and hear all from Laguardia from the hotel, it's really not walkable with luggage. Construction is a disaster at Laguardia and around the hotel. All the terminals are spread out. Shuttle runs every 15-30 minutes, I do not recall and just set up a time when you check in. They are great about it and it was simple for me.
Get an answer from Aloft New York LaGuardia Airport staff and past guests.