We're getting by.
Piper the cat, always reclusive, has come out of her shell since Snowflake left us. She has a whole new personality now that she's the only cat in the household.
And Layla is better than I imagined she would be. She's a high strung dog, and I thought she'd pace around endlessly looking for Lola. But she's sleeping more. And following my every move when she's awake.
I think she harbors some suspicion that I've allowed Lola to come upstairs (both she and Lola were/are confined to my downstairs due to their inability to cope with the steps.) She spends quite a bit of time time poking her nose through the cat door in the gate and sniffing.
Piper and Layla have always been tolerant of one another's presence. Maybe now they'll get cuddly.