I don't know how watertight the MOU's are. I never take any...

I don't know how watertight the MOU's are. I never take any party's word for anything, that's for the courts to decide. But they are no doubt partially water proof or at the very least water-resistant to a depth of 3 metres. They're also probably not money-resistant:

I would have thought seeing OBL at say 25% with some level of free carry and Buru and Mitsu at 25% each (assuming OXX remains part of the picture, if there weren't involved it would be different) would be a good outcome.
So maybe OBL is free carried through $3-4M of exploration (or whatever 25% of seismic and a Laurel drill in Derby is) essentially meaning they get $3-4M for that 12.5% (down 12.5% from 37.5% to 25%). I would have thought that would be a good deal for OBL given it's FOUR TIMES what Backreef's and OXX's share went for on a % basis.
Also for at least the last two years I've been assuming OBL end up with about 12.5% of Derby after a proper farm out ie in this scenario BRU, Mitsu, OBL, OXX all end up with 12.5% after a farm out to company X who gets 50%.

I'm not saying that's a best case scenario for OBL or anything.. Just that it's how I'd roughly see any compromise with BRU play out. I'm using pretty round figures here, I'm sure it wouldn't actually happen in perfect nice quarters exactly how I've laid it out. Here I'm just assuming OBL need exploration money, can't turf Buru out of Backreef's share outright and using round figures.

Others will prefer another of the dozens of scenarios with BRU involved. And then there are the scenarios where BRU win outright and don't have to compromise at all and have OBL fund their own 25% of costs (possible if the Laurel testing is successful and OBL can CR from a higher SP) and the scenarios where OBL wins outright and BRU have no involvement with Derby at all and farms out to a major or at least a mid tier.

Personally I see some form of compromise the most likely outcome as it's often the case that legals are used as a bargaining chip but I can't see the future. I don't have any knowledge other than what is public and haven't contacted anyone at either company about it.

Personally I'm not sure your split is absolutely fantastic because Buru has Mitsu involved and I'm not sure 37.5% between them is enough and it leaves OBL trying to fund a lot more of the seismic and exploration bill (assuming it's ideal to drill first to get a better farm out). If OBL hadn't got OXX involved it would be a different story as there would be more to go around.
It is however an entirely plausible scenario as it's still 75% of what Buru wanted and they would save almost $1M and probably just as likely as any compromise scenario I would outline.