We received our YES tickets in the mail as well. Ours arrived in February for our June trip. (We were able to select when we wanted them to be sent when we selected the option to have them mailed.)
Our group consists of girls and their families (or at least one adult). I gave out most to the families and had them connect with me on MDE. (I wanted to make sure that everyone could log in and access their own info from their phones or iPods in the parks, should they need make any changes. We also have a dining plan linked, so I didn't want people to interfere with another family's dining credits, which are also linked to their Magic Bands.) On the 60th day before travel you can begin making FP+ reservations. You must have tickets linked to each person. You are able to select these for anyone with whom you are connected or those whose accounts you oversee.
Be sure to check back periodically to see if there are any changes to the FP+ rules. According to the Disney Blog on their own website, they are working to allow more FP if you are Park Hopping. (Right now you are limited to selecting only one park per day and are limited to three FP. These can not be at the same ride. In EPCOT, you may only select one "E" ticket ride, and the other two are less popular attraction. This means you currently may not select Soarin' AND Test Track.) They said they would also like to offer FP+ guests the option of obtaining more FP in the parks after you have used all if you FP for the day. If that change is made, it wound be prudent to schedule your times earlier in the day.
Another tip that I discovered by accident. I have a Target Red Card, which gives me an extra 5% off when I pay for things at Target. I also receive a Pharmacy reward certificate periodically for an additional 5% off. On a whim, I picked up a Disney Gift card at Target and asked the cashier if I would also get the discounts on it. She said she didn't know but would see what would happen. I received both discounts. I quickly texted my
travel agent to see if we could use these to pay for the trip. She said that she had clients do it all the time. I purchased $2000 worth of cards for $1805. (It is not 10% off;it is 5% and another 5%). I scanned the cards serial numbers, sent them to my agent and she processed the payment. Several other families did the same thing. We have extras to be used to cover tips in the restaurants, souvenirs, etc.
To save a little more time and money, I have also been working with folks at Strollers and Groceries . They will be delivering groceries to our hotel. The individual families are letting us know what they want, and these will be packed for each family and delivered to Bell Services. This will allow those families who want to have breakfast in their rooms while getting ready some less expensive options. Also, things like bottled water are also much less expensive. ($8.00 for a 32 pack instead of $2.50 EACH in the parks.)
We are about 6 weeks away and are getting so excited!!