Thank you for your request.
In DyWorld there are 27 different chests (!). Making all chests compatible is definitely a lot of work. But I think that's not necessary. It would be great if they make the iron chest compatible.
Your mod is a really great idea and I really miss it in DyWorld Game. If you have the time for an extension, that would be great.
I have planned possibility to configure what chest type would be mergable. For base game that would mean that you could merge wooden, iron or steel chests. But only one type at the time!
Merging of multiple chest types wouldn't be a problem but splitting would be a massive problem. If you merge one 2 wooden and 1 steel how would I remember where they were before merge without massive memory requirements?