Shocks and Struts for 2015 Grand Cherokee

I'm a new member and not very knowledgeable about cars. I purchased our Grand Cherokee used with 22,000 miles in late 2015 or early 2016. It now has close to 108,000 miles and has been a very reliable vehicle. On a recent visit to our tire store to have tires rotated, the service person said the rear shocks are leaking plus he was seeing some signs on the tires that showed the shocks needed replacing. He gave me a quote for installation of 2 Excel Shocks for $484. (I am assuming that "Excel Shock" is the name given by the tire company, Les Schwab, but I'm not sure of that.} Since I had an appointment the next week with our local auto service business for a variety of fluid exchanges on the Jeep, I asked the service manager there to have the shocks inspected and to let me know whether they needed replacing. He said he could almost guarantee they would need replacing if they were the originals (because of the mileage on the car), but that he would have the mechanic check. The mechanic agreed, said they were leaking and needed to be replaced. They gave me an estimate of $602 and said the shocks to be installed would be KYB shocks, which, the service manager said, are very good shocks.

Next, however, he recommended that because of the miles on the vehicle, that I have the struts replaced also. The estimate specifies "NAPA Shocks and Struts Suspension Strut Assembly." The total estimate for that installation is $1750.

One other fact that may be important is that I tow a 21 foot trailer with the vehicle which has a dry weight of between 3000 and 3500 pounds.

Another fact that maybe important is that I have noticed nothing that would cause me to believe that there is anything wrong with the struts or shocks, but that doesn't seem significant to me because I don't know much about cars. I have read about the symptoms for worn shocks and have not noticed any of them.

So my questions are:

1. Is it worth the extra $120 to get the KYB rear shocks?
2. What are the risks of putting off replacing the struts and giving me some additional time to spread the cost?
3. Is the $1750 a reasonable ball park figure for replacing the struts and, if I do get them replaced, is the NAPA assembly a quality replacement?