Hi Beepster,
I actually do the kind of recording you're talking about every day. Some details about how we do it:
Platform really doesn't matter. I work with folks that use Logic and PT all the time, so when it comes to using Essentials, as long as they can record what they need to the platform shouldn't matter. Keep in mind that you're likely not going to have the same plugins across platforms even if you do use the same DAW, so why sweat it? Instead just:
1. Agree on a file format - we usually use .wav files at 48/24, and then:
2. Use stems. For example - I'll start a song in Sonar and write 2 verses and a chorus with some scratch tracks (drums, guitars and what have you). I'll export stems, usually by using busses and exporting them. Good bussing helps a ton here. I sometimes end up with a bus with only on track going to it...that's OK, it makes my exporting and organization easier. I'll then zip up the exported stems and upload them to a shared file service like google drive. The next guy, in my case usually my partner (who is primarily a guitarist), will download stems and write his parts along with any further composition (like adding a solo and/or a bridge). We then repeat for any additional composition or session artists. Once all the tracks are done I'll download all the tracks and import into Sonar to run through the SSL, mix and finish up.
The good news with stems is that other artists can do rough mixes to suit their monitoring needs. So for example, once I upload the first stems from my studio in SLC, my partner may change the relative volumes in his DAW to record his parts when he records in L.A. The same thing may happen for a drummer we hire in San Francisco so he can record his parts. Using stems makes that possible.
This kind of recording is increasingly common...so much so, in fact, that (at least in my experience) it's becoming more and more the de facto norm.
Good luck
Dean