The TS3650 will do what you want, provided you get good hardwood blades and a quality dado set. For IPE you'll need carbide, so keep that in mind for the dado set. If the dados aren't too deep, a 6" dado is cheaper and won't load the saw as much. It isn't really a job-site saw tho (at close to 300 lb its too heavy to move around in a yard without knocking everything out of kilter).
I'm assuming you have a good compound miter saw, which is what you'll need for the majority of the cuts, along with supports for the boards. If the supports are separate (ie flip top stands, roller stands, etc,) the TS 2400 will also do the job as for the ripping. I will let the TS2400 owners chime in with dado experience. A lot of people use routers for dadoes, so remember you'll need quality carbide if you go that route.
I can't comment on the Dewalt as I have never used one.
To reduce tearout on the dadoes, if you use the table saw (regardless of brand), I recommend you make a ZCI (zero clearance insert), preferably for only the maximum depth dado you will cut and different ones for different widths as needed (do a search on this forum for "zero clearance inserts" if this is greek to you). I recommend you also do this for your regular blades.
Hope this helps. Sounds like a fun project. I'll be doing something similar later this year, but can't afford IPE!
Practicing at practical wood working