New Member, New machine, Need help plesae

Hello, Bought a Kobelco 909 LCII excavator recently, mfg in 1988 and was pit machine for most of the 4000 hours on it, pretty good shape overall. We are in the process of reviving a farm and as such needed a big shovel. I need to multi-purpose this machine to be able dig, run a clam shell grapple, power a buck saw, and operate a feller buncher head, obviously not at the same time. We have a decent sized wood lot here and running a skidder and saw at the rate I have been going, I figure will take me 4 years to open up the lot the way we want to so I need to mechanize some of the operation. I plan to attach and run the feller buncher head by itself, and the grapple and buck saw as a pair, not looking to break any records here, just want to have some what of a back left when I am done. Ok, so I need to create a system where I have three new functions at the end of the stick, one continuous on / off, and the other two momentary with direction control. In addition, I need to create a single function down below the carriage for operation of the buck saw which will be momentary on or off. My thought is to tie into the pump and run a line up and over the boom and down the stick to a valve bank where I can have "fly by wire" valves to operate my functions at the end of the stick. Don't have a plan yet for the under carriage application. I called a local "hydraulic shop" to hire some help in doing this right - well they had never heard of Kobelco, told me it would take "multiple months" to add the plumbing, they would have to get the engineers involved, and at the end of the day it would be an $80,000 job, and that was just to to the part up and over the boom, I am serious. I am looking for input / direction here on how to make this work. I am not sure what to look for to identify the power beyond valve on my machine, or if they even installed on at the factory, so I need help there. Not sure how it all works below the carriage so I am looking for help in tying the buck saw connections there, I will not be moving the machine at the same time as I function the saw so I am guessing some sort of tie into the tracks would work just fine - thoughts? Lastly, how feasible is my plan to make the new stick end functions work? I would like to change or modify the joy sticks so that the new functions work by using my thumbs. Presuming I run full pressure and volume up and over the stick, can somebody point me toward a reserving valve that would allow me to always have the right volume and pressure of oil at the feller buncher head when it is activated and still allow the two other momentary arm functions to cycle normally in an open center set up like this? Any help and thoughts are greatly appreciated. I realize the final product will not perform as well as a purpose built machine, but for what I need as a one man show it sure beats the old fashioned way. Thanks