Comet Interceptor: parked in space, ready to fly to a new target at short notice

But.. couldn't we have few like that being already in motion and between slingshots at different corners of our system..

- if something like that could be at all possible.. (?) - what range of speeds could and shall they sustain staying in our system, being able to correct their course just enough for it, economically and for longer ?

- and how many probes bouncing in our system with such limits would be needed to at least be able to pass by any similar visitor/suspect like Oumuamua at some point or time really close - even if not matching speed or direction, then.. to do it just on its entry to the system or before it could be to late.. or to reach it gently even if late ?

- would it work similar for interstellar: couldn't we make our next probes be navigating opportunistically at longer range trying to come back home somehow (or self-destruct) ?