Cat peeing because she's mourning?

[Kesha12]

I hope I've put this in the right spot - this is my first post!

My cat Anais is almost 16 and in great health. We haven't changed the litter brand and her litter is clean (did a check list of all the normal go to ideas)

We had to say goodbye to our Boxer Nov 5th, so it's been a couple months. Initially Anais would go around the house meowing like crazy - and then that relatively stopped. But now, she has started to pee outside the litter box. She peed numerous times all over a couch that use to be Kesha's (our Boxer) and has peed on the landing on the stairs where Kesha use to sleep at night. I can't figure out what is going on? Could she be missing the dog (they were together 8 years) or is she happy she's Queen of the house again - trying to erase the dog scent? Thanks in advance for any help!