In addition to the comments on item 5, without the battery installed, the emergcy breakaway switch won't have power and the trailer brakes won't work in a hitch failure situation.
Never pull any trailer with electric brakes without a good, charged battery installed.
Rick & Debbie; Brandy, Dexter R.I.P., & Fritz R.I.P. (The Doxie "Kids")
2015 Jayco Pinnacle 36RSQS 5'er
2011 Rockwood Windjammer 3001W (Traded)
2013 Chevy Silverado 3500HD LTZ, 6.6L Diesel Dually; B&W Goose Neck and Companion 5'er hitch