Just Batting with top layer?
 

I am wondering if I can just use batting without any stabilizer under it, so would just have the somewhat heavy linen fabric I'm embroidering on and then a sort of thin cotton/bamboo batting underneath. I worry if I add another layer under the batting the seams are going to get kind of fat and unweildy when I piece it all together.

Also, if I do this, will it gum up my machine?
Thank you in advance for your advice!!!

i would use a really lightweight fabric or stabilizer under the batting so the fibers wouldn't clog up the bobbin area. if you're concerned about bulk, use a water-soluble stabilizer then rinse it off after embroidering.

When I do embroidery on a quilt, I have the fabric that I embroider and the stabilizer. Then I do the layering and quilting. I do not usually quilt over an embroidered design. But I have started the Quilt As You Go method, where I have done a quilting first on the block, layering the main fabric, thin batting and a stabilizer. After the overall quilting is done, then I put the design on. (I was making little soccer players and the background quilting was a soccer ball design. Then I was planning to use a backing fabric. (It's not finished - just one of my many WIP's.). My machine handled the layers with no problem. I do not use school glue to baste the layers together . Sulky makes a very light adhesive spray KK2000 that works the best to spray onto the batting. It actually dissipates after an hour or 2 but have never been gummy. You use a very quick spray in a small area.

I have done lots of embroidered blocks with just the top fabric and batting. The batting is the stabilizer. The only issue was sometimes poly batting tends to grab the bed of the machine a little, though I have had no mishaps. If you then want to quilt the block for QAYG you can put a backing square under, clip the sides to the embroidery frame, and quilt.

I embroidered quilt blocks with batting as it instructed but next time I won't as I still wanted to add a backing and do a bit of quilting to sandwich all the layers. And yes, the seams do get a bit thick using the batting when embroidering.

THANK YOU FOR THE RESPONSES! I gave it a go and it didn't go well. I think the embroidery was just too dense and it bunched up on me. But I learnnnnned something so there's that!