Hair lights aren't normally a problem as they're (well) out of frame, above, to one side, and slightly behind the subject. I normally use a beauty disk with a medium grid on a boom arm. The issue there isn't spill hitting the camera, it's the correct power and positioning of the light to illuminate the hair, but not put any undesirable lighting onto other areas (especially the face) (the overall exposure is governed buy the sum of any overlapping lights (eg if the key, fill, and hair lights all hit a common area of skin then that area will be brighter than if just key and fill lights had hit it - therefore the exposure will need to be adjusted, which inturn has an effect on the rest of the image) (it sounds tricky in theory, but in practice there's quite a bit of leeway -- you just have to be a little careful though).
Kicker lights are more challenging. Normally I'll put a medium grid on them, and then flag them off. HOW I flag them off depends on how they're positioned; I have a couple of approx 3 foot square flags attached to Velbon tripods (I knew I'd finally find a use for them!) - sometimes I can put them between the model and the light (but off to the side) so the flash can hit the model, but not the camera. Other times I'll bring a couple of 4' x 8' polystyrene sheets on wheels that I have in front of me (one side painted white, the other black) and just shoot through the gap in the middle. It's a bit clunky, but works well.
In the studio it's manual mode 100% of the time, but for location shoots, it's Av mode 100% of the time; heck the automation is there to make my life easier, so I might as well use it! Having just said that though, I also use off-camera flash lighting extensively (6x Canon 600EX-RT and a ST-E3-RT) (into a couple of softboxes) - meaning I can basically light anything. In that situation the only downside is that in Av mode the camera will regulate the shutterspeed to expose the background correctly - and that can mean all kinds of shutterspeeds (the flashes normally are just there to "top up" the ambient light. Sometimes I'm at 1/2000th (outdoors - sunny day - F2.8) other days 1/20th (indoors - poor lighting - F5.6). On the latter days it's a juggle of ISO / shutterspeed / flash.