Yes, that's right. It doesn't make any difference where the signals go to after they leave the 2235; they've already been processed by the tone controls, volume control, etc.
Again, the simplest thing is to just make the speaker wire connection; there's no disadvantage in doing so with the equipment you have. You could use just the one coaxial cable from either the left or right channel, but there's some possibility that a part of the bass from the other channel wouldn't be used, even though there's very little "stereo bass" in recordings and the sub frequencies are essentially non-directional.
