If Binance can list testnet coins then Idena has a good chance for inclusion, many people are now are aware of Idena but they want a bigger exchange for more volume, I'm glad that Qtrade accommodates Idena, so far I have no problem trading on Qtrade, I just become aware on how good Qtrade is because of Idena.
Getting listed before the mainnet is possible if the project is an ERC20, BEP2, TRC10/20 etc.. I don't think they list testnet tokens unless are very well established or is being listed on several exchanges prior Binance. But you will never know, is worth a try.
I also like qTrade, is a smooth an flawless exchange. Had no problem with them so far.