Is it an issue if I change my payout from BTC to BCH at anytime? I think getting paid in BCH works better for me because of low transaction/miner fees compared to BTC's high transaction/miner fees. Am I missing anything if I do this? What is the threshold payout for BCH? Is it the same as BTC (.01)?

Thresholds are the same; aside from decred; which is noted on the main page.
generate a new unique BCH address, and select payout in that; but that is assuming BCH is on the list of coins the pools actually mines.
Crackfoo can confirm.
Let me get it straight, i can get the payout in BTC even if i use antminer D3 on X11?
What does the d=40 stand for? Do i need it?
Does the password have to be c=BTC or c=BTC
correct; you are only selecting your payout coin type. you mine on an algorythm; not a specific coin. you only choose what coin you get paid in.
password
c=BTC,X11
or if you wanted a manual difficulty (not recommended unless you know what you are doing):
c=BTC,X11,d=40
Cheers.