Binance Smart Chain – What is the BNB Contract Address?

I think you can get Pool Addressess doing something like this. It's simple solution but you can optimize/improve.

from web3 import Web3

class getPairExample():
    def __init__(self, _token):
        
        #=== Setup Web3 ===#
        self.bsc = 'https://bsc-dataseed.binance.org/' #rpc 
        self.web3 = Web3(Web3.HTTPProvider(self.bsc)) #web3 connect
        self.target = self.web3.toChecksumAddress(_token) #checksum token


        #=== Setup getPair Contract ===#
        #= factory address
        self.pcs_factory_address = "0xcA143Ce32Fe78f1f7019d7d551a6402fC5350c73"

        #= getPair Abi
        self.getPairAbi = """[{"constant":true,"inputs":[{"internalType":"address","name":"","type":"address"},{"internalType":"address","name":"","type":"address"}],"name":"getPair","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"}]"""

        #= creating contract
        self.getPair_Factory_Contract = self.web3.eth.contract(address=self.pcs_factory_address,abi=self.getPairAbi)

        #= function to find Pairs
        self.getPair(self.target)


    def getPair(self, _token):
        pairs = []
        baseTokens = ["0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c", #bnb
                      "0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56", #busd
                      "0x55d398326f99059fF775485246999027B3197955"] #usdt

        for i in baseTokens:
            try: 
                get = self.getPair_Factory_Contract.functions.getPair(_token, i).call()
                pairs.append(get)
            except:
                pairs.append("Not Find")

        print(pairs)
        self.showPair(pairs, _token)


    def showPair(self, _pairs, _token):
        print(f"\nPancakeswap Pairs for token:\n{_token}")
        print(f"\nBNB Pair: {_pairs[0]}")
        print(f"\nBUSD Pair: {_pairs[1]}")
        print(f"\nUSDT Pair: {_pairs[2]}")
            
                

if __name__ == "__main__":
    getPairExample("0xe56842ed550ff2794f010738554db45e60730371") #put any token address here

Output:

You are paying the fees for the network to mine your transaction. So in case, Binance to your BTC wallet. Centralized exchanges generally charge more for withdrawls. Unfortunately, you dont have much of a choice here. If you plan to use BNB chain, you are basically getting wrapped BTC and not the actual stuff. They tend to be cheaper. But transferring to a cold wallet, use the actual BTC network.

For your 2nd qn - The BNB or ETH are required to pay miners/validators to process ur transaction. This is generally paid in the native chain token (BNB - for BSC and ETH - Etherium). I assume you want to transfer a BEP20 or ERC20 token.