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It appears that you have misunderstood the point about available length of residual bar that can serve the demand of negative moment. You do not have 990mm. I have already addressed that: You can provide extra rebars as per details shown by Ayesha. It is what it is! You cannot avoid them. What you can do is to limit their width so that the structure can have an longer service life, and the rebars remain corrosion free. I hope you understand that main/non-main depends on whether there is one-way or two-way action.

Negative rebars are the ones near the top of slab. With respect to my figure, it is the wall-rebar bent into the slab near its top face. It is a widely accepted practice to extend the top (negative) rebars to a distance of about span/4 from the face of support. For a 4m span, this would mean that you require 1m. But, as per your drawings, you do not have 1m; the available length of residual bars from the face of wall is about 1200 -150-300= 750. So you need extra rebars as per the detail shown in the comments of Ayesha for those spans. PS: In RCC structures there is no one-fits-all solutions. There are multiple loads paths. Even if you do not provide the lengths mentioned above, the slab can still have the required strength if you have provided extra reinforcement in the mid-span (i.e bottom bars). The difference will be that you might get wider cracks (on top near slab to wall connection) if you do not follow the detail suggested in my comments. But, you may not get to see them ever as flooring on the slab will make them invisible. This is the reason many engineers and contractors will say to you that do not worry about top rebars.