If I keep my ardr on bittrex, will I still receive my ignis is during the snapshot?
Don't keep your ARDR on bitrex, you will lose your ARDR. IGNIS is associated with NXT, not ARDR.
As far as I know, Ignis is associated with Ardor, because Ignis is the first childchain of Ardor. But the "airdrop" of Ignis is only associated with NXT coins. The snapshot will be taken from the NXT blockchain and NXT holders will be the beneficials from this process.