I usually use Adavantage,but i have used Broadline too
All cats need to be wormed and flea-dropped at the same time, as i am sure you know that its a cycle, fleas=worms =fleas
I have never seen a flea on my cats, but there again they don;t go anywhere there are other cats, either indoors or in the garden is where they usually are,and no cats come in my garden probably because i have a dog too, but just as a precaution, in case dog brings any in as of course she goes out , i flea drop ,and worm them about every 3 months,
Not sure about any other fle stuff causing deaths wxcept Bob Martins,
I buy all mine off the internet as much cheaper, but still the same as you can get from the vet