Does anyone have any new advice, as of 2017, on how to prepare my civil affairs packet?

Research it. Read the published packet requirements and follow them. Don't make up anything that you don't have and do not exaderate your skills or experience. This will quickly be identified during the assessment field exercise.
90% of the job is research and reports. If this was anything other than a job in USASOC, I'd be more than happy to give you the keys to the mansion but asking for people to basically do your packet, really is cheating yourself. If you can't do it on your own AND get selected, then you shouldn't be a 38 CMF.
Am I being an unhelpful ass? If the answer is no, then you have a chance. This is not a job which you will be spoon fed everything. You must be able to figure stuff out on your own else they (your team) will hate you. This is a job I which your given tons of freedom but with that are expectations. Put on your own or as a team, what is your score? Get my drift? I'm being harsh because anyone can be successful in the GPF but ca land is an entirely different beast.
I'm not trying to be mean, but they are a 4 man team and if your not up to par to begin with, then you will be failing yourself and the team.

SGT Wilson, be physically and mentally fit. If you speak another language go get and updated DLPT score and include the 330 form with your packet. Make sure you understand the guidance provided by the staff, if you don't understand ask! Good luck to you.

Sorry, no advice. The reserve side is a different animal and I went CA during the surge in 2006.
Although, I encourage you to go all out, it was the one of the best moves in my career.
Good luck!