Herein lies my problem, if the active termination circuits don't have anything to do with the "term[ination] power" then what or where comes the power used to keep them, well, "active?"
both active and passive terminators use term power.
Passive terminators are a bunch of resistors from the bus lines to term power.
Active terminators are similar, but as well as pull up resistors they have voltage regulators.
Wikipedia has a bit more detail
Parallel SCSI buses must always be terminated at both ends to ensure reliable operation. Without termination, data transitions would reflect back from the ends of the bus causing pulse distortion and potential data loss.
A positive DC termination voltage is provided by one or more devices on the bus, typically the initiator(s). This positive voltage is called TERMPOWER and is usually around +4.3 volts. TERMPOWER is normally generated by a diode connection to +5.0 volts. This is called a
diode-OR circuit, designed to prevent backflow of current to the supplying device. A device that supplies TERMPOWER must be able to provide up to 900 mA (single-ended SCSI) or 600 mA (differential SCSI).
Some early disk drives included
internal terminators, but most modern disk-drives do not provide termination which is then deemed to be
external.
Termination can be passive or active.
Passive termination means that each signal line is terminated by two resistors, 220 Ω to TERMPOWER and 330 Ω to ground.
Active termination means that there is a small voltage regulator which provides a +3.3 V supply. Each signal line is then terminated by a 110 Ω resistor to the +3.3 V supply. Active termination provides a better impedance match than passive termination because most flat ribbon cables have a
characteristic impedance of approximately 110 Ω.
Forced perfect termination (FPT) is similar to active termination, but with added diode clamp circuits which absorb any residual voltage overshoot or undershoot.
No term power, no termination. I doubt you can cause damage from enabling term power on any of the devices, no matter where they are on the bus. The only problem I could imagine would be a voltage drop, but the regulator in an active terminator will sort that out.
