First off, thanks for your military service! Welcome back.
For the overflow, maybe you could plant it somehow or at least use it for extra filtration. Since you already have it and its there.
As for lighting, I've heard a lot of good things about Finnex LED lights. Seem to be popular.
Filter, if your eheim doesn't work and you don't want to purchase another eheim, as they are pretty good, I would suggest Sun Sun canister filters. They are super cheap on [Ebay Link Removed] For a tank your size, you could get a Sun Sun for about $75 shipping included. They have some good reviews here on the website. When I finally decide to get rid of my HOB, that is what I'm getting after a lot of research.
Do some searching here on the forums and most of your questions will be answered. Good luck.