Yeah, noises down there can be hard to trace because your ears are so far away. One thing I've found that helps to distinguish between pedal versus crank/bottom-bracket noises is related to load. In going from no creaks to periodic creaks, the pedals tend to start first under light load. If the noise doesn't occur unless you have higher forces, that tends to indicate a crank/BB issue... in general, not always.
Easier to start from the outside in. Overhaul the pedals first and see if that helps. I find using several layers of plumber's teflon tape on the pedal-threads help avoid creaks later down the road. Then if it still creaks, move onto re-installing the crankarms. Rather than get into the debate on grease versus dry BB-spindle tapers, I just split the difference and use a single drop of oil on each of the taper faces. Be sure to use a torque-wrench and get the crankarm-bolt up to the required 25-33 lb*ft torque. This is probably the most common cause of loose-crankarm failures (if you bugger the crankarm hole just once from the bolt working loose, you pretty much will never ever be able to secure it again and a new crankarm is the only solution). And guess what happens before the crankarm gets loose enough to wobble and damage itself? IT SQUIRMS AND MAKES NOISE !!!!
Then if the crankarm re-install STILL doesn't remove the creaks, move onto rebuilding the BB. The threads clearance on the cups versus BB-shell are extremely loose and there's always going to be some vertical fretting & movement of the cups inside the shells. Especially on a newly chased and faced BB-shell. Some people use grease to fill the gap between the BB-cups and shell, but this dries out over time and you end up with creaking.
Again, I prefer 3-6-layers of teflon plumbing-tape over the BB-cup threads. And the number is very important. I usually start with a lot and work down. Typically 6-layers will be too much and the cup won't spin into the BB shell (although I've had a couple of bikes requiring that many). Remove all the tape and spin one 1 less layer and re-try. At some point, you'll get to enough layers that's stiff to spin by hand, but can be installed with a wrench. This is the perfect amount. I've had configurations where 4 layers was too many and the cups won't install. But 2 layers was too little and the BB still creaked. And 3 layers was perfect for installation tightness and no creaks!