Prevent Initial Sync when adding Google Account

So back in October, my wife and I both purchased the Note 5. We started using Google Photos, and I found a way to add both of our google accounts to each others phones so we could share our photos instantly. I had a problem adding her account to my phone, as it would sync everything (contacts, calendar, health data, etc.) immediately, but this did not happen when adding my account to her phone. I messed around with it for some time, and found an option that was not the same on both of our phones. (I think it was the backup account, but can't remember for sure). Whenever I disabled the option, whatever it is, on my phone, it allowed me to add her account without initially syncing. Keep in mind, my method for doing this on both phone was as follows every time I tried it.
1. Turn off Global Auto Sync
2. Add alternate account
3. Turn Off Mobile Data and WiFi so the phone was not online
4. Turn Auto Sync back on
5. Settings>Accounts>Google>(other account) and turn off Auto Sync on everything except Photos (Gmail in the case below)
6. Turn On Mobile Data and WiFi
Kerblam! Success.

However, I am trying to accomplish the same thing with another google account I have an alternate use for, but only want the gmail to sync. But no matter what I try, every time I add the account, it initially syncs everything. (I know this because next to every category, it says "Last Synced on MM/DD/YYY hh:mm) And obviously, all of my other account contacts, calendar data, etc. appear. I don't want to take the chance of just manually deleting everything after turning off the sync for each item in case the sync gets turned back on after some update or somethings, and it syncs the account with the phone and I lose everything. Has anyone had success doing this? I've been scouring the web for quite some time now with no luck. Neither Google or Samsung were of any help. Thanks in advance for any help : )