Reverb - Big halls don't work for all tracks, so yeah, you might want to use a smaller size. The parameter might claim it's 40m, but don't believe it. Use your ears, adjust to taste. And you don't have to have a long reverb. Length can be fairly short. The dry/wet ratio lets you adjust how clear a track is, so less wet means more foreground-y. You can filter and eq the reverb too, and the reverb plugin might have some options for that, like low ratio or something. At least filter out the lows. If you can set early reflections separate from reverb, you can give the reflections of your leads a longer pre-delay, so their attacks are clear, while the attacks of background instruments blends into the wet signal.
Of course, you can do a single reverb bus for the whole thing, or multiple (e.g. foreground, background, distant), or give each track its own reverb. Or some combination. Different methods give you different options, like full control over a reverb bus with eq and side-chaining, for example. Reverb levels per track matters, more reverb means more background-y sound. But track level is ultimately determines foreground-y-ness, reverb is an addition/enhancement to that. As is panning and eq.
Panning - Our ears easily tell where high frequencies come from, not so for low frequencies. Center is usually best. Usually. A stage-like plan can work, depending on the music, but I find the better way of thinking is to spread out frequencies, to spread instruments depending on their roles. Kick, bass and snare middle. The rest of the drumkit mimics what a drummer hears (so stage, but mirrored) with the amount of panning adjusted to taste. With the hihat panned left, other high-frequency percussion can go right, eg shaker. If a guitar goes left, another guitar (or any instrument occupying roughly the same frequency range at the same time) can go right. For this track, I wouldn't hardpan anything, I'd go for a kind of jazz club thing, with some instruments panned a bit, others not at all.
There are different schools of thought when it comes to panning. I can think of a few:
-No panning (stereo is just for stereo-recorded tracks and for effects)
-Listener-like panning, with variations:
-Drums from drummer or listener POV
-Drumkit and bass centered, or placed according to band
-Center and hardpan only
-Frequency balancing (works well for my tracks)