First off, welcome to the world of OM-D, where the lens choices are many and port sharing is infrequent!
The 7-14 is 114° at 7mm. The Oly 8mm 1.8 is 180°.
I have been shooting OM-D underwater for about 4 years now and I love it. I have experience with the 14-42 II R, the Panasonic 8mm Fisheye, and the Oly 60mm Macro. First off, the 60mm Macro lens is just awesome. Get that and don't look back. It is hard to get used to the effective 120mm field of view, but for small-to-medium stuff this lens can't be beat. Just temper your expectations. For any fish larger than, say, a medium angelfish, you won't be able to get the whole fish body in the frame without moving too far away for a really good shot. You can still do some good fish face work for larger fish. But there's an upside to the tight view, which is that you can shoot really small stuff without a diopter. You can, of course, use a diopter, but it's easy to fill the frame with small shrimp, etc. with no aids. And the image quality of the 60mm is just fantastic.
The standard port for the 60mm is 36163 (Macro Port 65). You can also use the 14-42 II R (not EZ) in this port without issue. If you want to play with the 30mm AND 60mm macro lenses, you could get 36135 (Macro Port 45) plus 36620 (Mini ext ring 20) and then use both lenses with the 45 port. The ext ring could also be used with the mini-dome (36132) if you shot with the Olympus 8mm fisheye.
In terms of wide, I would love to spend some time with the 7-14, but I don't own it. I do own the 12-40 Pro, but have not yet purchased the port for it, since that port is quite large and expensive. The 12-40 is a joy on land, and I would love to shoot it uw, but I'd need to find the port cheap. I can tell you that the 8mm fisheye lenses really take some getting used to. The 180° fov is very hard to light properly and consistently. If you can get it right, it's awesome. If you weren't planning on 2 strobes, then forget the fisheyes, too. The fisheye is not nearly as versatile as the 7-14 would be. It also locks you into fisheye-type compositions. I consider it a personal challenge to try and master, but a rectilinear would probably yield a lot more keepers. If I was buying now, I'd choose the Olympus 8mm over the Panasonic, but it didn't exist when I bought my setup. The weather sealing and a few more stops would be nice.
I like the primes and "zooming with your fins" because it's fewer pieces to keep track of in the kit. I have never bothered with focus gears, either. I find the low light autofocus to be good enough for my needs. Good luck and have fun!
Here's a 60mm and 8mm (panasonic) to wet your whistle

