Hi ec
I have been trying to fathom this Emma out for ages.
Emma married Edwin Outteridge, they were my great grandparents.
On the certificate Emma's place of residence is Oxford Restarurant, Tunbridge Wells, which fits in nicely with Speldhurst. I have located a William and Maria Stevens (the first family you mentioned) living at Groombridge Boarding School, Speldhurst in the 1881 census along with other siblings.
I had found the 1881 James Beeney etc but had no real proof it was my Emma but I suspect she is the one.
I think you are right the two families you found may be related because there seem to be a lot of Stevens living in the Rotherfield area at that time.
I really appreciate your help with this one, it has been bugging me for a long time, but with your help it looks as though I maybe going in the right direction.
Lindy Lou