How intentional were your changes in the tree structures? Your study is well done. I do have a preference for the original swelling out around the point of tree branches. I feel like you straightened the large tree in the foreground. This and a few other distinct differences look like you learned from but also were willing to make it your own (chimney, lamp, house back further...) I love the study.
I favor the nice lie for this case. Ask your father to tell the person that he likes that cat and wants to show someone else it. Or, that you wanted to show pictures of the cat to someone who can't believe how much the cat looks like theirs (have a name of someone who they don't know handy in case they ask. Better if that person lives far away so they have no chance to meet the person). Short of that: references online, trip to the pet store. The thing is without seeing the cat in good ref or better in person it is easy to miss some distinctive feature or other that will give the project a better change of success. By those pictures I wouldn't even be willing to commit to a color. Any chance you could get an invite over to dinner at their house? Best, option is to find some way to see the cat and maybe grab some snapshots when they are not looking.