Perhaps it is not so hard (I haven't read much of the game's code though):

1 - Tania's arrival in the town is detected. Could it be done the same way for a
hacked bot?

3 - Tania walks to the bar after her quest is completed. Killed and hacked bots
are obviously respawned on waypoints (at least console warning messages say so).
Would it be possible to let a robot go (instead of teleport) exactly onto a
waypoint where it then folloes the predefined path?

Of course there are other difficulties: Tux must lose control of the bot after
delivering it to prevent him from taking it away (either to bring it back to
have it counted multiple times instead of bringing in the required amount of
bots or to use it otherwise). Can faction and dialogue be "overwritten" with
something else as soon as the trigger from point 1 above is set off?

There should also be a requirement for certain types of bots (minimum level, for
example to be fetched from the glass path/swamp/sanctuary area or the shield
control "ground floor" levels) to make the quest a challenge and prevent them
from being killed easily by the lesser bots of the levels adjacent to the town.

Alternatively, if the usage of random hostile bots for this quest is too hard,
the quest could be to find and fetch bots who are already friendly, for example
from Omega Island. Modifying their dialogues and initiating a takeover game
should be easy. They could become hostile if Tux fails.