Complex sentence: The UNIMO leadership was skeptical of Bolikango's unified outlook for the Congo and remained independent, although he secured the support of the Ngombe, some of the Ngwaka and Bangala, and chiefs from the Lisala, Bongandanga, and Bumba regions.
Split into simpler sentences: The UNIMO leadership was skeptical of Bolikango's unified outlook for the Congo and remained independent. However, he did secure the support of the Ngombe, some of the Ngwaka and Bangala, and chiefs from the Lisala, Bongandanga, and Bumba regions.