Lighting Would these work?

The IP65 rating means it is supposed to be water resistant, I think IP66 is waterproof, but either way these multichip fixtures are kind of hit or miss. There is just a power supply/driver inside, and that is bonded for heat sinking to the metal frame inside, and also electrically grounded to it. The heat sink bond isn't always the greatest, and I've seen some where the electrical ground is loose. Talk about tear-apart videos, as well as personally taking one apart (which was a good one and I didn't see any issues)

The "good one" was one of those warm white LightingEver IP66 fixtures, and I've heard from several people that have got that shock/buzz feeling when they touch their scrubber, meaning there is something shorted or grounded out, so even the "best" fixture can go bad over time. For an AIO light in an acrylic enclosure inside the filter section, you would probably have heat/convection issues as well. Then, the multichips need to have a good distance from the screen (like 3" or so) or they will photosaturate right in front of the chip. Also there can be a heat issue on the glass, depending on the brand/wattage that glass can get pretty hot from what I hear, so you can't place a diffuser directly on it (unless it's also glass maybe), and the heat might transmit to the acrylic enclosure you put it in as well, which is not a huge deal, but it might craze over time.

So I guess the short answer is I'm not a huge fan of these fixtures...probably not the best for an AIO, at least not internally. Externally, that might be OK.

you could however take one of my LED boards and put it on a piece of aluminum (maybe 3/16" thick) that extends up to the top of the tank and then attach a small heat sink to it and that should wick away the heat enough to do the trick (and the top of that heat sink could still be below the top of tank), and it would be thin so it could fit in the space, and the LEDs are spread out so less issues with photoinhibition