A couple things I’d suggest:
Figure out which software you would like to use first and foremost.
Set yourself a price point (aka how much $$ you are willing to spend).
Then take a look at all of the available controllers and decide which would be best for your style, fitting in those above brackets.
Everything has it’s pros and cons, so it really comes down to watching videos or seeing perform live with the equipment IMO.
What it seems like you are looking for is almost a piece of hardware that emulates vinyl with the deck.
Honestly have you thought about going the CDJ route? I know it can be a bit pricier, but it looks like it could potentially have what you need in a well tested format. A lot of the CDJ’s are MIDI compatible as well, so you’d have that to work with, along side a mixer. And if I’m not mistaken, CDJ’s do have some similarity in features as the other options.
If you’re just looking for a great controller, I’d highly take a look at the VCI 100 and 300.
Sounds like your doing this with a buddy, and my suggestion would be this:
Traktor Setup:
Computer - Audio 4 DJ - VCI-100SE - Cheap 2 channel Mixer - VCI -100SE - Audio 4 DJ - Computer
This would allow you both to have virtual decks and the 2 channel mixer in the middle to switch between you both. I feel as though it’s probably the most cost effective setup, besides switching off and on the same equipment.
ITCH Setup:
Computer - VCI-300 - Cheap mixer inbetween - VCI-300 Computer
Now I’m not sure if I hit the mark at all, but that’s my 2 cents. The Otus seems expensive for what it is, but it may play right into your style. The Stanton 3d System is neat and either a great beginner tool or addition to a setup IMO. But I personally would see using other controllers and a 1d as a bonus for controlling effects/cue juggling possibly.