1st: do go for itachi or sai, both useless, kabuto is only good for group instance early on, and sa, so just 2* him.
2nd: Lucky Dice is ur best event for your ingots, make sure u get ur monthly pack, and imo make it possible to donate 1$ each day for daily recharge is so worth.
3rd: fire main, if u are not big spender get ur mind out of ninjas from events, and focus all events that u spend on power and power only, as a team tobi hinata iruka is one of the strongest early game teams with fire main.
4th: there is no choice beside fire main no matter what these noobs will come and say earth or go light,no, without kage ninjas fire main can't be beaten, braindead ppl like aristeaus,kaizer,scion,etc will say otherwise, but they have no clue about nauruto online anyway.
5th: keep ur seals and draw from kage if u want, also sage naruto is pretty much a must for exams later on, even after we get patched 120+.
tobi will probably be nerfed in 2-3 weeks, find a replace then, until then he can still carry at 3*