Do you really think i can get into top 5 NLUs with such air? I thought NLUs provide reservation(obc) to only state OBCs, and if that’s right then how will i be able to get into top 5? 

Yes, till AIR 3500, students have a fair chance of getting in top NLUs as there are seats which mostly remain vacant till the end. NLUs provide reservation to obc preferrably, but they look AIR of general category too and prefer them. So you have a fair chance in getting into NLUL. Plus there are 5 lists which comes out, plus after this, the colleges take out vacant seats list. With your marks, You will get into top 5.

Will i be informed about my selection in  these lists and vacant seats or will i have to check these things oftenly to get updates about seats

You will have to check it often over the websites. You can get the details there once they upload it. 

U will get rml for sure