Typically, you are supposed to keep your
ECV(s) in your room with you. Don't park them outside the room, in hallways, or other places that might block exit pathways in the event of any emergency. WDW CMs can - and do - move
ECVs that appear to be "abandoned" at Resorts.
You may be able to work with the Concierge and Bell Services to leave the ECV either at the luggage room or perhaps stationed in the Lobby while charging overnight, however, don't rely upon this happening. Bell Services at POFQ is typically quite crowded and busy, and in all the times we have stayed at POFQ we have never seen an ECV left to charge anywhere overnight since the new drop-off rules were started.
Plan on both units being charged in your room overnight - work directly with the front desk and/or the Concierge services folks once you are on the ground at the Resort to arrange for the table and chairs to be removed from the room. If they can accommodate one of the units outside the room, then it's a bonus.
As far as extension cords go, it's true that some ECV manufacturers state NOT to use an extension cord. Other's don't care. I own my personal ECVs, and as long as I use a heavy-duty extension cord (like contractors use on construction sites) then my batteries charge just fine, and it's much easier to deal with. Most of the rental units have chargers with long enough cords that you should be able to plug them in under/next to the TV at POFQ.
Be careful with "flags" - you need to make sure that anything you attach to a rental ECV won't damage the ECV - and more importantly, can't accidentally injure another guest. I suggest instead brightly colored matching bandanas or lengths of grosgrain ribbon.
Last but not least... don't be afraid to get separated - it can happen, and so just be prepared to text one another and keep each other updated. If you both have iPhones, then "Find My Friends" should be on the Home page of your phone (along with your My Disney Experience app!) As long as you are both clear on your next destination (whether it is a Park, the Resort, an attraction or whatever) you will both be fine!
