more possible total nonsense:what I do.
i would only do it as often as needed--when the filter slows down too much. and if your filter gets as nasty as mine when it's time to clean it, you might want to do the hoses outside, and not in the tub! ewww!
i do it the "wrong" way and have never had problems killing my bacteria: everything including the bio-media gets rinsed in tap water if sludgey (many recommend using declorinated or old tank water for this to keep the bacteria alive. maybe my water's non-toxic. maybe my bacteria all live in the gravel and ignore the filter. maybe i have two filters and if i kill the bacteria in one the other makes up for it cuz i am definitely too lazy to clean both filters at once.). i use a comfortable temperature because my tank is often hand-numbingly cold. i wash everything, and usually open up the little impeller housing and get that too. i don't like doing it so i clean everything with the stupid thought that i won't have to do it again as soon.
usually just this isn't enough to get full water pressure again. but i do it more often than a hose cleaning in the hopes it'll be enough. my hoses (especially at the connectors) get full of sludge and this is easiest to clean with a garden hose with good pressure.
so... how i would answer your questions...
-yeah, dump all the water inside. a little bit of water change is good for the tank anyway. but you can use the water inside the filter for rinsing the bio-media if you want to rinse it. in spite of what i DO, i would recommend NOT exposing your bacteria to tap water.
-rinse pads and media container? yep. or get new pads if you have goldfish because they get too nasty to clean. they're cleanable but why put yourself through it? (my current filters have noodle ceramic thingies to catch the big crud and they rinse pretty clean without all that TOUCHING.)
-hot or cold? doesn't matter too much, but tank temp is probably best because there are going to be some bacteria on the sponge and might as well not try to kill them. if you do a water change in your tank at the same time, you can use the old tank water to be really careful.
-how often? i can't really say. definitely when the thing gets clogged, and that's a good enough indication for me because mine does clog fast (goldfish+dead plants). i have a non goldfish planted tank and the filter takes a few months to start slowing down. as long as you have decent flow and good water parameters, i'd let it be. something on the end of the intake that pre-filters and that you can easily clean more frequently is nice to have.
some filters won't re-establish suction (without sucking) if you fill up the canister before re-attaching it. does the ECCO have a self-primer? the manual probably tells you if you should fill it.
then clean the bath tub.
i do this as infrequently as i can get away with (filter, not tub. actually, now that i think about it...). even with greatly reduced flow and a huge bioload, i don't have water quality issues. but since it's a low-tech system where the filter output is the only source of water movement, i have to keep it running or the goldfish become very unhappy. they are sort of demanding when it comes to oxygen.
what do the rest of you do?