Yes! 

I can’t find it rn and so I can’t remember if it was an ask directly sent to me or just a post I reblogged… 😛 sorries… but someone had reported that they and their friend (significant other maybe?) were in a funeral parlor, owned by a relative I think, and were allowed to climb into a few coffins to test that question, and YES, two full-grown adults were able to fit comfortably in a standard-size coffin. Louis and Lestat are both 6 ft tall with Lestat being slightly taller, so yeah, that’s a lot of person when doubled. It was also unnaturally tall for that time period.

^IDK if the coffins in the movie were accurate to the time period, probably yes. That one looked plenty big enough for them to both get in and why didn’t they!!! but I didn’t see any cushions at all, that might have made the fit a little tighter. 

Currently, ppl can have custom coffins made, it would be easy enough to order one of any size 😉