If she's on a 4-hour EASY with only 45-minute naps, guaranteed she's OT probably by lunch, let alone bedtime, and probably tunning on sheer adrenaline by evening, so a restless night is almost a given.

You say she doesn't seem to be in any pain but have you tried pain meds before sleep time? Nat surprised us by popping her first two teeth around 4 months, precocious little so and so.

Is there any chance of reflux, even silent reflux? On the Colic/Reflux/Crying board is a Reflux 101 sticky with some symptoms to look for and things to try. Has she started solids? If so, may be a food reaction or tummy-ache.
For the NW, since she's escalating into a hard cry, I would go in the moment you hear her stirring and try resettling before it escalates. The more wound up they get, the longer it takes for them to resettle, by and large. I actually slept on the girls' floor on a couple of folded-up quilts (some people use an air mattress) so I could jump on the NW's before they escalated. We did have to wean that, but at the time it kept them from waking so fully most of the time, and I had the option of just letting them sleep with me so we could, well, SLEEP and break the OT cycle - and then once they AND I were better-rested we could set about sleep training. I also delegated some of the NW's to DH - he would do anything before 11PM and after 4AM since he had to get up early for work anyway, so I got a block of time in the middle.
Even Ferber himself didn't recommend CC or CIO for babies under 6 months, so I would do your level best to avoid it especially so young. It's so so SOOOO hard when you're sleep-deprived, but it can really cause all kinds of things to go wrong, not the least of which is outright fear of the crib/cot altogether, which can really mess up any sleep training you're trying to do, which is why BW and CIO really aren't compatible.