The DBE 885 suggestion on the profile is still active: see this link.
It looks like he served in the 4th US Infantry and (later) in the 8th US infantry. Am I reading that correctly? So, is the key question which regiment he should be placed in?
The rule for categories generally is 'However, a profile should never be in more than one category in the same hierarchy.' (https://www.wikitree.com/wiki/Help:Categorization#How_to_Categorize_a_Profile). So I assume he should be in only one. I didn't see an answer in the help for military categories (https://www.wikitree.com/wiki/Space:MilitaryHelp-Military#Third_Level_-_Primary_Categories_for_Profiles)
The Category for the 8th regiment US Army is here: https://www.wikitree.com/wiki/Category:8th_Regiment_of_Infantry%2C_United_States_Army%2C_Mexican-American_War Unless I missed it on the list, the 4th US doesn't exist yet.