Possible but probably a lot less nice to set up given AE barely provides proper tools for this.
Compositing in linear however is not something new. ACES with the OCIO plugin just allows you to easily convert different camera or display referred images to one common domain of choice to work in and treat the equally making it easier to composite material from different sources.
Because ACEScg is a linear colorspace you can use this as the sandwich to do all your effects in but doing it in linear rec.709 or linear Arri Wide Gamut would be equal in math if I’m not mistaken.
It’s just that ACEScg (AP1 primaries, linear gamma) is the choice of workingspace for a compliant ACES workflow. ACEScc or ACEScct is a log version of this colorspace for DI / colorgrading.
You can choose rec.709 as working space without linearize checked. Using rec.709 encoded footage like that insert and Arri LogC file won’t be converted by After Effects resulting in the same behavior as Preserve RGB. You still work linearly because you are in 32-bit and ACES converts it to linear by going to ACEScg.
You can be sure with this setup that when you export, profile embedding will happen as expected and as added bonus if you were to do final composites going to display it’s easy to add graphics on top without having to struggle with the fact that the entire project is in linear ACEScg.
For anything that isn’t rec.709 you would have to check preserveRGB though otherwise it converts it to that first. Things like cg renders in .exr you would Preserve RGB.
I’ve made an example setup from that same project earlier. Maybe that helps.
Just keep in mind that we aren’t telling AE we’re working in linear so if you use Camera Lens Blur you have to uncheck Use Linear Working Space and for Exposure check Bypass Linear Light Conversion.
Not all effects benefit from working in linear. I think denoising for example is preferred in log. And not all fx in AE support 32bit. Using Lumetri is definitely ‘broken’ in linear I think as it’s controls were designed for rec709 normalized or log and a lot of other color tools probably too. Doing color adjustments in log should feel much more natural compared to what you are used to.
What does feel nice is anything blur, glow and exposure.
Lastly I’d say this is all great and I find being able to use ACES for composites in AE really cool but so far I’ve rarely used it because working in 32bit just destroys performance in AE compared to other software. If you can live without it for simple composites I’d always do it unless there really is a specific reason to use it. 
Maybe once we get OCIOv2 with ACES 1.3 we can run on GPU and it might be faster!