Question 1, answer: That is the materialistic way of worshiping. Materialists are always careful for maintaining his material status quo first, and then please Visnu. Although they profess to be devotees of Visnu. Therefore the Krishna Consciousness persons are greater than such materialistic worshippers. Materialist person perform all pious activities or devotional activities for some material gain, and as soon as there is any hindrance in the path of material gain, they at once become demon. Therefore bhakti means without any material desires. That is the sign of pure devotee. He has no motive to satisfy his material desires by devotional service.
Question 2, answer: That is just his military spirit, that Bali Maharaja says "If He be the illustrious Lord Visnu not desirous of foregoing His own fame, He shall wrest from me this earth after slaying me in battle, or He shall be slain by me." The last portion of this question is not very clear.
Question 3, answer: Why Bali Maharaja is considered a Mahajana: Bali Maharaja is Mahajana because he wanted to serve Visnu by disobeying his non-bona fide spiritual master. As explained above, Sukracarya was hereditary spiritual master by seminic succession. But Bali Maharaja first revolted against this stereotyped seminic succession spiritual master, and therefore he is Mahajana. Srila Jiva Goswami has described in his Karamasandharvha that one should be anxious to accept a spiritual master who is bona fide in spiritual knowledge. And if need be one should relinquish the connection of hereditary spiritual master and accept a real bona fide spiritual master. So when Sukaracharya advised him contrary to his previous instructions, specifically, he checked Bali Maharaja in the matter of worshiping Visnu, and thus Sukaracharya became at once fallen down from the position of becoming a spiritual master. Nobody can become a spiritual master who is not a devotee of Visnu.