I, too, have several friends with same names, some with a capital letter and some with a small letter. In fact, I have 3 Michelle's. Where this causes problems is when one of them send you a gift. It only shows the name of the friend but does not show the level number with it. The game does display level numbers every place else but there.
So, I recently have been trying to keep tabs on what people request or gift to me so I can know better which friends I may want to delete. I received a gift from one of the Michelle's. So I sent a message to each asking if they sent the gift and told them I was having difficulty determining who sent it since I have 3 of them. Then I asked if they would be willing to add an initial to their game name to help with this problem.
Each wrote back and said they added an initial to their name. Then I thanked each one and checked their wish lists out and sent a gift, if I was able and left tips and woke the sleepers or sent a charging gift and advised each one that I did such.
I know it's a lot of extra work, but most are agreeable and grateful when they get a gift in return.