If a similar topic exists I apologize - I can't think of or find one. Anyway, I will start things off with two contributions: one tip and one trick.
* The Gen I and Gen II Leafs can use the same car covers. This may well vary by brand, but the lined cover with mirror pockets that I bought from an Ebay dealer (info lost, I'm afraid) for my 2013 SV also fits our new Leaf Plus SV. It seems to fit it just as well (about 90% perfect) as it did the 2013.
* You can make a level cargo floor even with the Bose sub-woofer. You lose about 4" of cargo height, but in most cases it's worth it, and it's easy to reverse for a taller load. Just acquire a Weather Tech Leaf Gen II cargo mat, leave the cutout for the sub-woofer intact, and cut support blocks from whatever rigid or flexible packing foam you have at hand. As long as the blocks are within an inch or so of the height of the sub-woofer, and you have enough of them to support substantial loads, the cargo cover will now provide a level cargo floor, and conceal the sub-woofer. (I don't know yet how it will affect the audio quality.) You can now use that 4" concealed space to carry an EVSE, tools, whatever will fit. This should also work for the Gen 1.5 2013+ Leaf if the cargo mat is similar.