I think the last time I looked at the dipstick it had a cool engine and a hot engine level. Also know that the BG flush, used at my dealership, uses chemicals to clean the sediment out of the system. I would not do the full flush after 100k if it has never been done before as I have heard horror stories of the chemicals cleaning grooves out of the trans causing huge problems afterwards.
As for Fluid type: Alldata says
DRAIN AND REFILL: 3.1 qt. (2.9 L, 2.6 Imp. qt.)
FLUID TYPE: Genuine ATF
Just looked up the other gen1 years and they also say 3.1 d&r however, the 04 says that a dry fill is 7.2 qts.