Specifically in FRLG, I have not faced the E4. However, the advice I'm giving is easy to deal with in every game, regardless of the opponent.
You need to consider the types of the E4, and find the best types to field against them (super effective). Your movesets should be able (on one Pokemon) to counter its main weakness should that be a problem [but you'd most likely be playing the advantage ASAP]. The other thing I would mention is to make sure not to double types too much. I understand that the Legendary birds are powerful, but for a Fire-type Poke, I would much rather have your Charizard. That Pokemon is well-trained, and its moveset is exemplary.
That being said, if you wanted to make that a team, you could do it. One question I do
have though is why you have two Ice types and
two Fire types? I won't even worry about all of the Flying hybrids you have which will be easy pickings for Bruno's Rock-type Pokes.
I would try and get a more average level spread across your team. (Why are you only carrying 5 Pokes on this team?) Train the others to a much more similar level before hitting up the E4.
If you haven't considered the types yet, I would make a suggestion of a Psychic. Or a Grass... (Exeggutor?)
Hope this helps!
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