*8 channel snake to connect the ADAT outputs to the mixer Line Inputs. 1/4" unbalanced T/S will be fine.
*A TRS Insert Cable for each outboard compressor you want to use on a channel during mixdown.
*A Pair of powered studio monitors, and two balanced cables to connect them to the monitor output of the console. XLR or 1/4" TRS, both styles will work fine, depending on your monitor's connections.
*An outboard CD burner (or computer with DAW software), and the appropriate cables to connect it to the main mix outputs of the console.
Also another pair of cables to connect the CD burner's outputs back to the "2 track" monitor input of the console, so you can listen to your finished mixes.
*And, ideally in this scenario (IMO), you need a dedicated mic preamp (not the console) to feed input to your ADAT. It is simple enough to reach behind the ADAT and repatch your mic preamp input cables from channel to channel, I did it for years. This way your console is always in "mix" mode, trust me it's far easier to work this way than to use the console's mic preamps and have to constantly switch which mode the console is in.
So, add a simple external mic preamp to your list, and some 1/4" cables to connect it's outputs to your ADAT inputs.
*Should go without saying, but obviously you need a few mics, mic cables, stands etc.
*Headphones and a couple headphone extension cables.
*SVHS tape for the ADATS, that might actually be the hardest thing to source...
If I were you, I'd look for a Fostex unit that uses the internal hard drive instead of a tape based unit...
I had good luck with ADATS for years, better than most people's luck, but they can be a pain in the ass for sure.
My best advice on ADATS is: Don't stack commands too fast, IE: Don't hit "stop", then immediately hit "rewind". Or "rewind", then "stop", then "play" in quick succession... That will result in some chewed tape before you know it. Always give an ADAT a second between each command. If you treat it like an old man it will behave a bit better, if you rush it it will bite you in the ass and chew up a tape.
Actually, it could chew up a tape at any moment's notice unfortunately, regardless of how careful you are.
I advise against digital tape, but the basic idea of your studio could be awesome and fun. And portable, which is very cool.
If you search GS, you will find that most people here *HATE* ADATs, and will spew all manner of loathsome venom at you for even thinking of using this heinous technology. They are not necessarily wrong...
The ADAT hate is a bit overblown, but I am an ADAT lover and I am advising you to find a hard disk based solution.