I'm planning for my next villain to be a cyborg husband-wife team...

Just exaggerate their personality traits into physical ones. Technology lets us do the stuff we want to do, so follow "what they would want to do" down the line. One doesn't like being touched? They have insulated layers of electricity-outputting panels in their synthskin -- anyone trying to grab them gets zapped. One likes watching people suffer? Darts or sprays loaded with agonizing toxins. Et cetera.

You're right, I probably should explain a little more. I was trying not to get bogged down in the setting too much.
The first one is the de-facto ruler of a planet, which produces a lot of technical equipment for the empireits part of. Cyborging people is banned though, so this has been done pretty secretly (only a few people know). She's very imperious and ambitious, and has ambitions of creating an new monarchy-style system for her planet one day.
The other is a previous member of her personal guard. Doesn't share the same levels of megalomania as her, but enjoys her company and is morally ambivalent enough to put up with her more maniacal impulses.

Doesn't that depend on the system?

I'd like one be a super speedy melee character and the other a heavy weapons ranged guy.

Personal guard goes fucking invincible so he can protect her.

She screams at them to not mess with this senator as she activates her nanite dispersers.

It matters if someone is planning on going toe-to-toe with a tank-killer in the setting or not. Or is paid to do so on a daily basis, for that matter.

I should also add that the technology to do this is pretty much unhead of due to the ban (the setting is pretty low-scifi apart from this) so ideally I'd like something that would suit a big 'oh shit' reveal.

Make them like this

Megalomaniacs are often also very paranoid and very protective of their own lives, especially ones who are in a public political situation and live in fear of being shot or poisoned. Assassins aren't unheard of, even in relatively peaceful times. So it would be very likely that she chose her augments based around having an absurd amount of survivability. Like "take off her head and she still can frown at you" levels of survivability, if possible. Of course, the kind of paranoid who is constantly worried about being assassinated is probably thinking about doing so herself to someone, so she'd also probably want weapons that are undetectable and concealable. Of course, a heavily aug'd punch satisfies that, too, but also so do finger-lasers and cranial guns. She'd also, as a politician, probably want inhuman amounts of information on threats, both as a political advantage and, did I mention paranoia?

The guard is probably ex-military. As such, he probably has been in enough actual military situations that he considers the proper method of dealing with threats to be proactive -- making them dead first. Expect incredibly advanced reflexes and some increased speed and maneuverability as well, as well as some of the usual aug'd strength. As well, he probably has faced enough annoyingly close-mouthed prisoners of war that he would like a way of solving that. If cyborg parts can interface with brains and memories (and they can now -- look up neuroprosthetics!), then that implies other people's brains can be invaded, and so if he takes someone captive, he probably has a tool like Robocop's data spike... except it works on your nervous system too. It's probably hard to conceal an armor-penetrating weapon, so instead he relies on what he actually carries, but he might have radio scanners (and has tagged some items to make backup weapons caches -- or his wife -- easier to find) or a super-nose to detect the smells of gun cleaner and explosives.

You can, of course, go increasingly wild on these themes, depending on how far you want to take the technology of the setting -- maybe she has her brain backed up! Maybe he has a wireless connection to a platoon of robot guards he can control by thought. And so on and so forth.

Oh, I didn't specify what senses the politician might have. She'd probably have IR sensors so she can literally watch people get hot under the collar, increased hearing so she can listen to people whisper to each other in the next room, and if possible a sensor that would let her snoop on local communications so she knows what people are saying to each other. Also, both probably have the ability to turn the "volume" up and down on these as they will, though they might be surprised/pained at a sudden sound still. The guard probably explicitly has a pain editor, as well, in his remaining fleshybits, and part of the reason he might be so seemingly nonchalant and ambivalent is that he modded his brain to be that way even if he's busy killing people. Beats freaking out in a combat sitch.

I'd have the fight deep down in a government research facility, with the PCs trapped near the bottom. The Husband stalking the halls, trying to ambush and strike down the PCs ala Alien; while the Wife is opening/locking doors, activating unfinished projects, venting gas and taunting the PCs from the control room ala Glados/Hal.

Its a nice idea, and I might try to crowbar it in somehow, but as it stands it looks like the PCs are going to try some sort of assassination attempt of their own (read: storm the place), so a scripted-ish scenario like that one might be hard to pull off. That's the joys of TTRPGs though, isn't it?

>>"Make one ranged, make one melee" is super-dumb. A couple operating as a pair would eventually develop synergistic strategies -- not one where one is constantly fouling up the aim of the other.
You don't see the synergy of having them cover each other's weakness?
What kind of retards would clump up? The melee guy flanks while the ranged guy provides suppression
You sound super-dumb