New myself but I had a leak in a similar place (I posted a thread a few weeks back).
I've gone down the route of taking the oil pan off (after removing the subframe) and will be fitting an oil pan brace. I've also got a new o'ring for the oil level sensor (£6 from Mazda) and new engine mounts (not Mazda) as it looked like they had gone too.
While I was in there I've got new drop links, ARB bushes, toe links and 8kg/6kg springs to replace the 12kg/10kg springs that were fitted to it. I've also sent a few pieces off to the powder coaters.
Not the small job I planned but hopefully will start putting it back together in the next few days.
I might be wrong but are the threaded holes for an engine stand? I checked my pictures and the one on the right is empty but the one on the left has an earth strap attached to it (the black/yellow wire in your picture).