Final answer:
Characters likely to regret Tom and Huck's visit to the Phelps's include the Phelps family, other slaves, and members of the local community who could face consequences from the boys' actions and efforts to free Jim.
Step-by-step explanation:
The characters likely to be sorry that Tom and Huck ever came to the Phelps's are those who would experience disruption or harm as a result of their presence and actions.
This includes the Phelps themselves, who could face social and legal consequences for housing runaway slaves if Tom and Huck's activities were discovered, and potentially other slaves on the farm who might be punished for any chaos caused by Tom and Huck's scheme to free Jim.
Also, extended family members, neighbors, and the local community may be upset due to any disturbance created by the boys. The visit by Tom and Huck introduces unpredictable elements into the lives of the Phelps and can upset the social order, especially if it was known that they were helping Jim, who is a runaway slave.
Additionally, considering the historical setting and viewpoint of slavery during the period, those who are proponents of slavery and maintain the status quo would likely be displeased with the boys' interference, reflecting societal norms of the time.