I don't believe this is possible, as they tightened security after Goldrenrod's Radio Tower incident (Source the guard at the bottom of the stairs).
you cant
The Copycat is in Saffron City, near the train station.
You can either get it by capturing it in Pokemon Silver in the Safari Zone. Or by trading it on the Global Trade Station in Pokemon Diamond, Pearl, or Platinum.
There is no Poke Flute item in Pokemon Silver. Instead, the player can have their radio upgraded in Lavender Town. It will then play a station that can play the Poke Flute tune.
I would suggest the Global Trade Station. Deoxys is an event pokemon and the event has long since passed
Well First you have to get to the kanto reigon after beating the elite 4 and go to wher the Pokemon grave yard used to be and ther will be a raidio station and u go in side and u talk to the old man on the bench and he will give you the pokeflute
Go to the Pokemon mart in the town with the ice gym beat team rocket then go to goldenrod train station or the raidio place then you can get past the guy
25
Silver Trench has 99 floors, but you'll meet, battle and recruit Lugia on the 99th floor.
99
you can't
You get the poke flute from a man at the raidio tower in Kanto after you clear the power plant in Kanto and beat the Cerulean City gym leader.
goldenrod city
There are 99 floors in Silver Trench & consists of predominantly water-type pokemon. Lugia resides on the 99th, and has a recruitment rating of 99.9% when you go up a second time. Floors 15 35 55 75 are just HUGE monster houses
Silver Trench has 99 floors and on floor 25, 35, 55 and 75 (I think) are giant one room floors that are monster houses (thats what makes this dungeon infamous)
You can't.
You Can't