most of the stuff on the engine(like wiring) can be removed!
along with most sensors, they are old world rotary stuff, not much use when you go to aftermarket ECU and sensors.
basicly you will need gages for oil press., engine temp., boost press., fuel press., RPM, most will be available from the ECU supplier.
water from the base(sump), is a sure sign of bad rotor housing seals, but possible cracks in housings or side plates(irons),the thing is you will have to take the engine completely apart, and examine everything internal.
taking sump off a rotary engine wont show much,except the bottom of the rotor housings, and that aint much to see.
but looking at the bright side your learning curve is on the up stroke.lol.
the engines are very simple, almost to simple(EXAMINE EVERYTHING CAREFULLY).
wearing parts, that can be expensive, are rotor housings, and rotors themselves, the APEXs run allover the map for cost, best to stick to factory stuff if you are not after serious HI HP, anything over 350-400hp can be expensive.
be careful of used wearing parts,!
mount the engine on an engine stand,and start to take it apart, stand thet can rotate it for front to point upwards.
something of interest for you,i have some left over rotary parts, they are in storage, let me know,and i will make a list, with prices? also pix.
shipping may be hi-tho!
and YES its is cold temps here in central Texas,very unusual, that polar vortex, is here also!