Re: No audio jack
Waterproof is great, but here's the question to ask yourself: how often do I use my phone in the pool, and how often do I use my earphones/earbuds?
When I was like 8 years old (ie damned near 40 bloody years ago!) I had a waterproof radio that had a headphone jack. The jack was sealed, basically a standard one coated in rubbed IIRC. This was in the '80s. Surely firms with the tech knowhow that Google has must have someone who can figure that out. If not, Google, I am currently seeking work and I can design lots of trivially simple ways for you to waterproof stuff!
It really is trivially easy to do.