Hair won’t ever export. Grooms are an engine only BS thing.
Clothing you would probably need to export separately and re-assemble.
Generally, you can export an Animation and select to also export the mesh.
So save the pose as an animation, then export that animation.
For every piece of clothing.
Then deal with creating the hair from scratch in a way that can 3d print.
Then merge it all to a single object. Delete internal faces. Make sure its as manifold as it can be (nose holes, ear holes, etc).
Take it to cura or similar. Add supports where needed. Probably under the hands.
Definitely under the lab coat if its down to the knees, not necessarily that short.
And print away for 12 hours…
Note that you probably have to remove the gaps between the labcoat and the model below it entierly or you are just going to print a mess.