No Lift 360 Swap Tips/Suggestions

You could probably leave the hood on, I have done that before, however this being the first time for you, it might be better to just take it off. Before you loosen any bolts, mark the location of the hinges by using a felt pen or a scratch awl so that when you reinstall it, it's simply matter of lining up the marks. I don't recommend propping up the transmission with a jackstand, but if you have no other option it may be ok. Just remember that once the engine has been separated from the transmission bellhousing, the only thing holding it is the transmission mount, which is pretty much at the back of the transmission. As for the flexplate question, I am not well versed in the Magnum engines, but I do know that the torque convertor difference between LA series 318 and 360 is a balance weight, one requires it, one doesn't. Memory is failing me on which one is which.
That said, if the Magnum flexplate is balanced to the engine, then it stands to reason the 318 convertor is ok.
You will see once you begin that accessing the torque convertor bolts is via removing the sheet metal plate between the engine and transmission. You will also have to remove the starter before pulling the engine.
I strongly recommend that you take some time and at least watch some YouTube videos on the engine swap procedure before you dive in and find yourself in a bad situation, unsure about how to proceed.

Just my .02.