Why did you need to take hydraulic hoses to the engines, unless you didn’t have hydraulic steering to start?
Having done a good number of these installations, plus replacements and servicing, I strongly endorse those three little high-pressure ball valves for pump isolation. Without them the boat is rendered inoperable is the A/P pump needs to be removed, and you will likely drain almost the entire system.
JMHO
You have the luxury of having done it a few times...
Before I learned about the Parker field replaceable fittings, I bought new sets of pre-made hoses from helm to tees, tees to motors, tees to pump. You are correct, if I cut the original hoses and put new fittings on, I would only need the new short ones to the pump from the Tees and a compensation hose, and a short one for the Shadow Drive.
I calculated later that the best scenario is buying 1 set of pre-made hoses the full length helm to motor and 6 of Parker part# 2TFMS-6-5b fittings. Then use the old hoses to make a compensation line and three 2ft hoses--- for pump to tees and the Shadow Drive to helm. I found that 2 ft pre-made hoses cost almost as much as 14 ft hoses so buying the long ones lets you use the old ones for the short hoses...you save on fittings because they already have some crimped on...
as for the valves....I decided that since the Garmin Smart Pump has screws to shut the flow of fluid to it at the inputs, if it had an internal leak I could isolate it. Then at the dock I could disconnect the short hoses at the pump and cap them with 3/8 compression fitting/caps before losing much fluid.
It would be nice if Garmin gave out part#s/brands/sizes of those valves..and all other fittings....If I had not wasted some money on too many Seastar brand fittings and hoses I might have done the valves...If I wasn't left guessing which ones to use.. If you have a particular valve you've done well with, please share the brand and part# and your source.