Sounds like one one pump for the water features (spillways). A 2 h.p. full-rated pump (same thing as a 2.5 h.p. up-rated pump) with 3″ suction and return would be more than good enough for that application. A sheer descent type waterfall usually requires a minimum flow of 10 gpm per foot, so you’d need at least 60 gpm. Heck, even a 1 h.p. medium-head pump, like a Whisperflo, can put out like 90 gpm at that kind of distance and pipe size; a high head pump, incidentally, may be more appropriate for this use. And don’t use a bigger pump than is required, since the electricity cost is so much more.

Now, for your spa jets … Are we talking one pump for filtration, heating and jets? If so, and if you’re using 3″ suction and return, six jets (the type known as “number 7″ jets, the most common type) should be OK at that distance, assuming there’s not a lot of 90-degree fittings and such. As a rough guess, if you use a low-loss backwash valve and keep the fittings at a minimum, your head loss ought to be on the order of 65 ft.

And, yes, there are ways to figure out what the head loss will be. There are charts available that show friction loss through various pipe types, and for fittings. Manufacturers have loss charts for most major components, if you can get them. It gets a little complicated, but it ain’t rocket science. Perhaps the easiest thing to do is get the figures from a similar existing installation: put a vacuum gauge in the front pump drain plug, and a pressure gauge in the rear one. Multiply the vacuum reading by 1.13 and the pressure reading by 2.31, then add them together. This is the total head loss for the system.

Hope this helps.