External Speakers, do you really want them ?

The quality of Marine speakers is very subjective. For instance, these specific Marine speakers are way better than most peoples home stereo speakers

Bose

With todays remote speaker setups all you really need to do is just bring one outside and it works where you set it.

WALMART AMAZON etc has all kinds of different WIRELESS speakers...

Roy Ken

I'm not a big fan of cutting holes in exterior walls to install speakers.
1. Anytime there's a hole, there's a chance of a leak.
2. That mounting space compromises the insulation.
3. Most weatherproof speakers don't have the best sound.
4. There are better ways to achieve exterior sound than mounting a speaker into the wall.

I see from your pictures on your blog that the dust cap of the speaker has become unglued from the cone. You can just glue that cap back in place and, as long as the rest of the cone and surround material is intact, that should fix your leak. That is pretty rare and I would bet that it has something to do with the material of the dust cap.