Hi Jennie
With the zylkene it's 1 per day if he is under 5kg, 2per day if over 5kg. Jagger has 2 per day, one with his breakfast and one with his tea.
Wow, you've had it all going on, haven't you? Poor Nala! How was Simba while she was away and how were they both when she came home? It's always handbags at dawn here when one of them has been to the vet and comes home smelling different!
I honestly don't know about the change in food. Food-wise, I feed mine a combination of Meowing Heads and Thrive as I also try to avoid kitty junk food. But you might have a fight on your hands now they've tasted Felix and whiskas! Having said that, our two were being fed kitty junk food by the breeder and I managed to change it. I guess it will be trial and error, finding something that is good in your eyes and yummy to them. My two really love the wet Meowing Heads hey good looking wet food. It's always gone in seconds. What treats do you give them? Perhaps put a couple of treats in the food to tempt them?
I would have thought any bedding shop should have waterproof mattress covers, or of course good old Amazon. I think the main thing is to cover the areas to avoid the urine getting on the sofas etc again as that is cheaper than replacing mattresses and sofas.
Even though Jagger has been fine since he's been back on zylkene I'm still worried he will wee somewhere he shouldn't again. Hence if he cries at any time, day or night I'm up and checking if he needs his tray and that its clean and Hendrix hasn't used it. I've been cleaning all the trays again today, it becomes an obsession
Jagger was still sniffing the rug he pee'd on a few weeks ago, I've cleaned it with enzyme cleaner but he could still smell his urine. I've been spraying it the last few days with feliway and he isn't doing it so much now thank goodness.
I pm'd you the details for the Behavioirist in case you want to go that route. She has bengals so she knows what she's talking about.
I'm sure you will get there, cats don't like being 'dirty', so something is wrong in his world and it's a case of trying to work it out... Have there been any new animals around your house at all that he might be sensing? There are so many things that could be upsetting him, trying to actually pinpoint the cause can be really hard!