AFMAre 250 hours in 12 weeks enough for this exam?

12 weeks is certainly enough. I started studying for this paper immediately after the June exams, had a 2 week holiday in July and still passed it first time in September. I probably studied a lot less than 250 hours in total.

my question is....are OT lectures with OT notes plus revision kit of BPP are sufficient to pass this paper? or we must do study text as well...any opinion.. i passed my all foundation exam with OT lectures notes and revision kit. but i m not sure whether this approach works with professional level?

i would recommend reading textbook if you are self studying. a significant portion of the exam is theocratical. so reading thoroughly will help you understand stuff. then practice, practice ..