First, you can give up on this for now unless you're already created such prototype before :- ) This is not a work for one or two weeks.
Second, Unreal doesn't allow imported baked maps (Shadow and Lightmaps), so it doesn't matter if Corona will support them in future, Unreal will not support importing them any soon.
Only Unreal can currently generate all baked components by itself from light using Lightmass to reflections using Probe captures.
You can't transfer materials, since Unreal doesn't use specular/glossiness maps (not even inverting them would help since they are on curve in Corona for odd reasons) and neither bump maps.
You have to manually re-create them all. Same goes for lighting, Unreal only uses 2 bounces for Skylight, but up to 100 for analytical lights (Sun, Reflectors,etc..), so you won't create identical look.
Simplest way how to accomodate your client for now would be rendering bunch of 360 perspectives in Corona and embedding those in Pano softwares on website.