The LT1s oil pump and drive is basically the same as any other smallblock chevy, the problem is the distributor in mounted to the front of the motor and directly cam driven so instead of the distributo driving the oil pump it is a dumby shaft exactly like the bottom few inches of normal distributor. So where on an old SBC you would pull the distributor and prime it, there is no distributor or even hole there on the LT1 you would have to pull the intake, then that little dumby shaft. If the worst happens a junkyard LT1 does not have to be expensive I got mine with lots of extras for $550 and only 40K on it, one thing that helped was it came from a Roadmaster, same motor the SS got but without the SS premuim added to the price.
Before putting my motor in I pulled the plugs and sprayed fogging oil in, I bet seafoam deep creep would be great too. Then turned it a couple times by hand and changed the oil. Once in I defeated the fuel and spark systems, the fuel by unplugging the FP wiring under the trunk, then cranked it till the dash showed pressure, let the starter cool and did that a few more times before firing it. Over 40K since and added a bigger cam, all is good. Really I think you are worrying a bit too much but being overly cautious is better than having just jumped in and fired it with that nasty formerly oil crap in the pan.
Before putting my motor in I pulled the plugs and sprayed fogging oil in, I bet seafoam deep creep would be great too. Then turned it a couple times by hand and changed the oil. Once in I defeated the fuel and spark systems, the fuel by unplugging the FP wiring under the trunk, then cranked it till the dash showed pressure, let the starter cool and did that a few more times before firing it. Over 40K since and added a bigger cam, all is good. Really I think you are worrying a bit too much but being overly cautious is better than having just jumped in and fired it with that nasty formerly oil crap in the pan.