Welcome back, You sound like me I was out for 28yrs. I was a FO guy back in the day too. I know what you mean about researching your way out of it. I run into paralysis by analysis all the time. I'm like you I researched things to death.. But I finally came to the conclusion I will get no place till I just jump in and do it. I chose to go in deep. You can see my build in my Signature block. I honestly wish to some degree I went a little smaller. But we shall see where this goes.
I'm going to be 100% blunt with you. I would not go with that tank (assuming you are looking at the AIO). I would lean towards a system that has a lower sump. Yes, they are nearly double the price for that size but so worth it. The added water volume and space availability to do so much more makes them worth it in the long run. With the AIO (all in one) systems you quickly find you run out of space to add doodads. Because lets be honest, you will want to get more stuff as the tank grows. SPS systems need more work too. That tight little space in the back of an AIO just is a pain to work in and very limiting. Can it be done.. Sure.. But I wouldn't because I like convenience and extra space to work in.
As for your lighting choices. I would lean to the 2 Primes. The reason is that you can spread them out to suit placement of corals. With the Hydra you might find it limiting on placing things. Shadows being cast and so forth. 2 Primes will do a great job of providing blanket coverage of the tank. You could start with just 1 prime and add a second later. They have a nice spread and one will cover a tank that size for a while. My honest opinion is you can never have enough light spread on the surface. You can always adjust the intensity of the light so it's not to bright. Also you might consider a 24" T5 hybrid system for a smaller tank like that.
If it where me and that size footprint system is what I was looking at. I would go with the NUVO EXT Lagoon 25 and the 2 Primes. Also you will need to buy or build a small sump for this tank and buy a pump so keep that in mind.
Take all my advice with a grain of salt, I have only been back into the hobby since June 2019. I have 4 tanks now in my house. 1 is a QT with 4 fish in it getting treated for issues. 1 is a Coral/invert QT, 1 is an all in one 10G Nuvo pro that is going to be a coral QT but cycling. Lastly is my Red Sea 625 that is cycled and just waiting for things to get done in the QT. I am able to only speak from my own research and little experience on the hobby so far.
Good luck and hope to see you posting a build soon.