Yes, it will do what you want. It accepts up to 6 analog inputs, with phantom power switchable in channel pairs. You can make a "monitor mix" of those 6 inputs, with control over level and panning of each channel (or level and stereo-width, for any channel pair which has been set to Mid/Side mode). That stereo mix is routed to the headphone jack, and can be also routed to the analog RCA outputs. You can also choose to record (or not) that stereo monitor mix to the additional "stereo channel", which is sometimes referred to here on the forum as "channels 7&8", however the stereo channel does not have the same functionality as channels 1 through 6. The "stereo channel" is stereo only, and can only record only the stereo monitor mix or a separate digital input.
It's not really a true 8 channel recorder but a 6 channel recorder, which has the additional capability to record either a stereo mix of the 6 inputs, or an additional stereo digital input.
The recorder does not provide any delay or EQ capability. It can only playback the 6 channels concurrently, or the stereo channel by itself, but not all 8 at the same time. There is no level control over output of discrete 6 channel playback, but there is level an panning control over the stereo mix output of the 6.
As fsulloway mentions, it is better mix down after the fact when you can more accurately hear what is going on with the mix, yet there is no reason not to go ahead and record a live stereo mix along with the primary channels other than consumption of additional SDcard space. If the live mix isn't all that, you can always remix using the discrete recorded channels / channel pairs.