1.If you have got only 49% in PCB than you have to guve the 12th exam again as you need atleast 50% in 10+2 in PCB . So no need to fill your old marks as NEET and the colleges will not accept your form

2.During filling the NEET form next year it would be better to fill appearing as you will have to enter your new class 12th result . 

1. Yes you can get admission in any medical college next year if you score minimum of 50% in 12th in PCB and also score decent marks in NEET 2020

Best Wishes 

Era Madaria