For gathering intel and tailing, shadow mice are the best, because they are highly intelligent and understand human language.
But for scouting an area, the insects are the best things.
Zoi termite queen let all the termites cover all the area around the mansion and started spreading throughout the estate.
The mansion is in the deeper part of the estate and it is mostly covered with the impact crystals which are toweringly high in some places and at the same time make it almost impossible to peer into the mansion from a distance.
So, if the other party really wanted to keep an eye on Sam, by employing a human, he would be able to find them in no time with the zoi termites.
Even if the shadow mice are good, they are better suited for gathering intel and tailing. But for scouting a particular area in a short amount of time, insects with a queen are best.