Infracted for insulting people for no apparent reason whatsoever =/
Also the traditional order of succession for monarchies is that the line of the eldest child always has priority over the lines of the younger children. Meaning that Scarlet and her children by default are higher in the order of succession than Viola and her future children. That Viola is elder than Rebecca is irrelevant because Rebecca is the child of the successor of the throne.
The original order was:
1. King Riku
2. Scarlet
3. Rebecca
4. Viola
As Scarlet has died, Rebecca is the next in line if Riku dies or resigns.
Of course this is based on the assumption the traditional order is followed, which is not necessarily the case. King Riku has shown to be quite unusual in these matters, there are other systems to decide succession and it's still a fictional world. However as this is the most common way of succession, it has statistically seen the highest probability of being true till stated otherwise. In the least it's no less baseless then your claim that Viola is the queen and then you even start mindlessly insulting people despite your statements aren't any better...