Hey JuliaDee,
Elasto is not a good material for small, highly detailed parts. Any embossed detail will grow and any engraved detail will shrink. Anything that is 8x8x8mm will print out with little details and probably a huge size difference than what is intended. It might grow to be about 1.5x1.5x1.5mm once printed.
Second, having a lot of loose parts in the build makes the entire tray harder to depowder. Right now, our production facility has asked for a bigger minimum box size.
You can sprue them together, but make sure the sprues you use is 1.5mm in diameter, otherwise it would likely break in production.
Last, please remember that this material does indeed grow. Any items that needs to be tight fighting or accurate down to the millimeter, I would try in another material. Embossed parts tends to "grow" up to 0.8mm and engraved details can shrink up to 1.0mm. For something that's super small, 0.8mm is basically doubling your size! The minimum bounding box are there for a reason (to prevent designs that lose all detail in printing, to print designs that "grow" to where the size doubles).. so even if you "fool" the rejection, this is still very much a reality.
I hope that helps, let me know if you have any more questions.
Thanks