It looks to me as if you will need pull up resistors for those encoders, there does not appear to be any other components on the Rutex encoder interfaces apart from the terminal to socket items, before I purchased anything like this I would expect to get a detailed description from Rutex or whoever I am buying from. The fifth terminal is possibly either a shield connection or maybe an index pulse, if the encoder had one.
If you run say 20awg shielded cable, could you not run the cable direct to the drive?
There is an Australian Electronic supply house that is now advirtising in N.A. (I forgot the name) but If they are large enough it should be easy to find.