I'm never sure about pet insurance. They try to market it to us occasionally in school (ha. ha.), but not much as buyers but so we'll try to persuade clients in the future to buy it =/

As far as companies, this seems to be the better one:
http://www.petinsurance.com/
They have a lower-cost plan just for cats. They also have emergency-only type plans, like the ones that exist for people. There are a number of different options on there, like if you want routine care stuff (exam/dental cleaning/vaccines/bloodwork) covered, or just illness expenses covered, etc.

But, I can't help but wonder if it's better to do what semiveg does. Yeah, there's a chance that you'll end up saving more than you spend on the insurance, but there's the opposite possibility as well. I think that one of the reasons that people like pet insurance is that it's an easy 10-15$ per month (at least for cats), and then when expenses come up, they're mostly covered. You could save that money per month and have a fund, but I think that's the thing - most of the time people don't plan for vet expenses, especially emergencies, so when one comes up it's $2,000 that you don't have, at least not immediately available.

However, I've met a lot of people who LOVE having pet insurance. It's one of those things that they'll say "I don't know why more people don't have this!" For me, I considered it, but since I've got 4 cats a good plan would come out to a total of 80/month for me, whereas my vet care has been pretty cheap (except for one cat! ugh), and it's discounted while i'm in school, and most practices discount it for their vets, so...  they don't really give us an incentive to try the product they want us to sell.

For cats and toilets, some people have great luck with that. Honestly, not all cats are very trainable. That is, many cats are not especially motivated by their human's approval, and many are picky about their food, so there goes giving them treats. But some cats are great for that. For the litter training thing, it kind of takes out that middle step of training that you'd use in a dog (rewards) by slowly converting their litter box into the toilet bowl.
That being said, there is a concern with cats going to the bathroom in the toilet. As far as I know, the water waste treatment does not actually treat for two diseases that cats often carry - Toxoplasmosis and Giardia - so there's a bit of a health hazard there. Apparently they've found that cat giardia does not, in all likelihood, actually affect humans. But toxoplasmosis is a particular risk for people who are immunocompromised, like small children, older persons, people undergoing chemotherapy or who have HIV, etc. I'm not sure how likely one is to get infected from drinking water if there's, idk, less than 1% of cats in a city using the toilet as a toilet, but it's something to consider.
I know a lot of newer owners are interested in the cats-going-in-toilets thing, I'm guessing because of the new inconvenience litter boxes provide. It's kind of nice to not have to scoop poop or smell the litter as much. But, if you get a good, clumping litter (I use Litter Purrfect from Costco, but Scoop Away is similar and also good; neither are very expensive either) and one of the slotted scoops, it's pretty easy. I tried out a number of litter brand when I first got my cats (including some natural-er ones), but these ones I found to be the best for scooping and the best at covering up odor.

For behavior... if one's more dominant, it's just the dynamics. Usually it'll manifest as someone stealing someone else's food, or getting jealous when you're giving the other cat affection and trying to get in your way ;D If your cats are the more doting type, they'll just end up that way and you'll be the "leader" without doing anything. If they're more aloof, there's not much you can do other than be their faithful servant.
:)