So I am running a Steelbound fighter in an Iron Gods campaign who has chosen whips. Assuming I get a monowhip, what, if anything, can I use for the monowhip? Can I use it as my bonded weapon and/or use the whip specific feats (weapon focus, serpent lash, and others)?
It counts as a whip when it is activated
From the weapon's description:
A monowhip is a deadly melee weapon capable of inflicting horrible wounds, even in the hands of the weak. An inactive monowhip looks like a short metal baton, but when it’s activated, a small weight detaches, revealing a 15-foot-long monofilament length. Wielded like a whip, a monowhip slices deeply into targets and can inflict grievous critical hits with shocking ease. Attacks made with a monowhip resolve as touch attacks, and they ignore hardness as if the monofilament were made of adamantine. A monowhip’s damage cannot be enhanced by strength, as the monofilament slices with equal ease regardless of the force applied. Activating a monowhip is a move action; once activated, the whip consumes power incredibly quickly, at the rate of 1 charge per round.
Basically, for all purposes, an activated monowhip counts as a whip, for as long as it has charges left.
As for the Steelbound fighter archetype, you need a bit of GM Fiat there. It counts as a whip when it's activated, for all purposes. Otherwise, it's a metal baton and not a whip, which is not a valid target for Steelbound Awakening. It's up to the GM to decide if it can be a bonded weapon or not in that situation.
Personally, unless the player is able to find a way to supply it with power indefinitely (which is possible), I would say it's not a valid target for that ability.
For instance, we know that you can install a Power Generator in a technological weapon. Those generators yield a certain number of charges per hour, which can be used to supply any technological gear. Considering that a Fission Reactor Generator can supply 1000 charges per hour, and we have 600 rounds of combat per hour, you could use one of those to keep your Monowhip supplied with energy 24/7. Then, I would consider it a valid target to become an intelligent weapon.
A monowhip counts as a whip as a weapon
According to the general rule of technological weapons:
If an existing weapon proficiency allows the new weapon’s use, that weapon proficiency is listed in parentheses.
The monowhip entry has Proficiency exotic (whip) listed, so it is considered a whip whenever a whip is needed as a weapon. So most feats and class abilities will consider a monowhip a whip.
Depending on your GM a monowhip might not be able to be used for more utility things, such as grabbing small items. This is not because it isn't a whip, but because:
A monowhip’s damage cannot be enhanced by strength, as the monofilament slices with equal ease regardless of the force applied.
As a result you will probably still want to keep a non-monowhip around.