To move beyond Mahogany Town, you will first need to visit the Goldenrod City radio town to clear out Team Rocket.
cindber island
In Blckthorn City
Yes.
in the ice cave before the 8th gym
Blackthorn city, in kanto you find him at cinnibar island show him your 7 kanto badges to make him go back to the gym then you can battle him.
Unless your Delibird is pretty high leveled, I don't think that it would be very useful in a gym battle.
move to the 8th gym
Blue is the 8th kanto gym leder.
you have to get lugia
beat the 8th gym leader and then talk to to professor elm :)
Yes, you get it by Professor Elm.
Blue (The eighth gym leader) is waiting on Cinnabar. He won't battle you unless you've beat the rest of the gym leaders