Forgot to attach the immigration record I have - here it is - as well as a few additional details. As far as I can tell, Oto immigrated alone in 1911; perhaps this was the return trip with his wife and children. The family appears on lines 10-13 of both pages of the passenger record, attached.
Michele Bongo of Ariano, Oto's father, is listed as his closest relative in Italy, and Angelone Capozzi, brother-in-law, is listed as closest relative in the US (5 North Sq, Boston). When Oto first immigrated, he listed brother-in-law Michele Manganiello (3 North Sq, Boston) as his closest relative in the US.
Bongo, Sampietro, Capozzi and Manganiello all seem to be Ariano names - I'm guessing that Capozzi and Manganiello might have been married to Oto's sisters, although I suppose they could have been related by marriage through Maria, instead.