Sure it can! Channel Cats can tolerate a wide variety of Water parameters and temperatures.
Do I think that your channel cat will make it in the long run? Probably not, I'd say .....If the RTC gets big enough he'll swallow him up one day. If the Channel Cat has a big size advantage over the RTC there might be some fighting or beating or what not.... I've tried it in the past with the Channel cat having a huge size advantage over the RTC and it worked out until my RTC caught Ick and died.
yea channel cats are beastly when it comes to tolerance for different types of ewater params and temps. they are not real agressive but like any cat will eat naything that fits in it mouth. i have a channel with a jag right now and he is fine