Unless the travelers want to actually see downtown Colombo it might be better to consider one of the airport hotels.

I have stayed at the Tamarind Tree in their suites which I think most people would find acceptable for "an overnight". And the buffet meals are as good as the fancier hotels downtown. Less than ten minutes by taxi. And should be a whole lot less than $100 / night. Book on the internet or through the airline.

OTOH, if beaches entice you, Negombo is not that far and there would be the possibility of wandering through the tourist shops nearby.

I would suspect at this point in time ALL Sri Lanka hotels would be appreciative of any customers.

Happy wandering

Fred