Jak,
For your lens selection, you would never use the 14-42 when you have the much better 12-50. You would need two ports, the 4" dome for the 9-18, and the dedicated 12-50 port/gear (that port can also house the 60mm macro). In terms of compromise, I think from my use that the 12-50 flat port gives you much more on the macro end than what you lose on the wide end, which is still decently wide. I can go from scenics and turtles to nudibrancs and blennies in seconds and if you want wider you use the 9-18. For ultra-macro use the 60 in the 12-50 port. You would have everything from wide to ultra-macro covered and a lot of versatility.
Yes, that 12-50 port and gear is expensive, but it is my most-used lens and gives you incredible options on a dive.