I just decided to simplify and moved to an LX10 from a Canon DSLR setup. I used the new rig for 10 dives last week. To answer the first question -- you can save a lot of money by going with the INON UWL-100 with our without the accessory dome. Image quality looks a bit worse from the reviews than the WWL-1 but maybe not much. You can get both the UWL-100 and the dome for $700. Having said that, I went with the WWL-1 mainly because of the bayonet mount feature. Way back when I used to shoot compacts with the 67mm threaded lenses and found threading them on and off to be a bit of a pain. To use the WWL-1 as bayonet mount, you need a separate bayonet mount adapter on the housing. The Nauticam housing comes with 67mm threads. If you get the WWL-1, I recommend getting the buoyancy collar, though that makes it even bigger. The buoyancy collar also complicates trying to nest the WWL-1 on an arm mount. With the collar on, an 8" ULCS arm is barely long enough to park the lens there. I cann't imagine trying to take the WWL-1 underwater without the collar, however, unless the intent is to leave it on the housing the whole time.
To answer the macro question: The camera, itself, does not excel at macro. If macro is all you want, maybe consider the TG-5. I got the CMC-1 wet lens, but did not play with it much. It requires yet another adapter to attach to lens so you can attach it to the housing adapter to be bayonet mount, but it is worth it to me to only have to turn a quarter turn and have the lens lock into place.
In my limited test drive, found the camera to be fairly responsive, though switching from a DSLR is a learning curve. I was impressed with the wide angle capabilities and the video seems very clear, though I need to get up to speed on white balancing. Macro is much different than with a DSLR and 100mm lens. That will take some getting used to, as will going back to having shutter lag, even if it is relatively minimal. However, I was able to leave an entire suitcase home this time because I didn't have to carry lenses and ports. That is keeping me happy.
I will be even happier if I can find a better way to park the WWL-1 underwater. It is a beast.
I also need to get a bit more buoyancy onto the entire rig. I am using Stix floats but the lens caddy takes up a lot of space, displacing the floats.
According to the retailers, they are selling quite a few LX10 kits so they have to be out there somewhere.