I want to say the beta patch is the PSP patch, but I'm not 100% sure.
EDIT: By this I mean the patch itself for that version, not saying it will work with this one.
From what I remember BlargSnes already has DKC 1 on the compatibility list: http://wiki.gbatemp.net/wiki/BlargSnes_Compatibility_List
Also can confirm that Shin Megami Tensei I&II and Kyuukyaku Megami Tensei work(At least the first parts)
I think someone posted something like this on the Homebrew section if I'm not wrong. Although the only edit it allowed was changing it for the game case.
What kind of mods are you talking about?
If it is just skins and texture packs then you should be able to play online without problem. If it is actual modding (Damage output and similars) I think you can't play online at all or with a friend unless both of you have the mod. I might be wrong but...
Then I'll keep an eye on this thread, they did say that most of the text would be translated for september I think, so probably for early 2017 or really late 2016, either way I can just wait till then.