doffing in certain clusters rewards a chance for a purple technician and other various ways (when reaching certian commendation maximum rank)
but the technician needs aux2batt abilitiy to have the effect triggered, it doesn't generally reduce the ability cooldown. it says so on the fron description, but if you read the specific description you'll see that you need to have auxilary to battery to activate it's effect.
Is the link to the wiki that outlines the mission chain details. You can get all the doffs before you even start the chain and you can even replicate all the materials beforehand. If the wiki page is messed up just scroll down until you see the mission list. Look for "Colonization" and expand that. You will see a bunch of missions...7 missions which are the original chain and 2 repeatable.
The 7 missions in the chain you can use the lowest quality doffs, it does not matter if it crits or not. When you do the last part 7/7 "Renown" you get your first technician doff, which is blue quality. That last part 7/7 Renown also doesnt matter if it crits or not, you get the blue quality technician regardless. Keep in mind that you can only get the doff from Renown once, so be careful about making a decision to discard him. To get the rest of your doffs you need to keep going back into the B'Tran cluster (either admiral or normal version of the cluster) and scout out the repeatable missions that you need to run. The repeatables are named "Support B'Tran Colonization Efforts" and "Support B'Tran Cluster Expansion Efforts". They are not directly part of the 7 part chain mentioned above, but the repeatables wont become available until after you finish the 7 part chain. Now with the repeatables you DO have to crit it in order to get your purple quality technicians. And you can run it multiple times for the same purple technician doff.
I've done the chain on two characters. My first character ran the repeatables three times...the first one crit and gave me my first purp technician, second one did not crit, third one crit and i got my next purp technician doff. I think i got them both on the same day for that toon. Now on my second character, i am up to 9-10 completions of the repeatable and none of them have crit. I started scouting for the repeatable mission when i started at tier 1 rep (about 5k rep) with new romulus/omega/nukara. I am now at 46k rep and after 9-10 non crits i still do not have any purps Once i hit tier 4 rep with new romulus i will get my MK XII rom-plas weapons and if i still have no purple technicians i may just buy them from the exchange.
EDIT: ohh and the first character had common quality doffs of the correct type and with 1-2 crit traits being used for the repeatable. My second character has been using rare quality doffs also of the correct type and with two of the crit traits for the repeatable. So yah...i guess RNG is still RNG