am assuming this is a concrete structure, when shifting service toilet to utility area, and if there are apartments above, then running extra lengths of supply/drainage lines & introducing a structural sink slab (if this is concrete) under the new location can be charged extra.. it will be easier to divide the 3rd toilet. all services will be already available. only, do check on supply & drain pipes capacity as load is increased on the same pipes which were serving one toilet earlier..

I think a comfortable distance between the island and the counter is around 42". It seems that you have only 30" between your cook top and the counter. I might be a little too tight. The wall between the entrance and the kitchen could be 4' long instead of 6', you would then be able to move the island a foot which would give you more room between the cook top and the island. Could you switch the location of the toilet and vanity in your dad's bathroom so your enter facing a vanity instead of a toilet which is a lot nicer.

I'd open it above like a 'pass-through' and bring the table out in front of it with a bench under the opening.

i used the 3 +1+1 because it allows for more flexibility for moving around the room i suggest that an L shaped sofa would block access to the sliding door and/or the front entry, perhaps 2 x 2 seaters could also work and/or you could try swopping the lounge and dining areas but that arrangement doesn't allow wall space for a TV