You should also include the Flames of Night and the Earth Flames. Those are another Non-Vongola flame power. And again, as I previously stated, during "that arc" in which flame weapons were mass distributed everyone had the ability to call upon their own flames. The fact that everyone has the potiental to utilize flame like abilities means that flames are not strictly for the Vongola. 

Well, you also have to consider that DW Bullets exist in various different types. There's the one Makkuro uses and that other depressed guy, etc. DW bullets are hardly strict to any one family. 

Also, I intended for her to be able to go into HDWM without bullets or pills. It is cannonically possible, as it has been done already. I intended for my Mafia boss character, which is totally different than just your regular associate or follower, to be able to willingly initiate the HDWM. 

As for flames I created my own flames :0
As far as I can tell, custom flames are not barred. Another thing I brought up was that you cannot say for sure if other mafia families cannot use flames. There is evidence to the contary, though there isn't evidence that is a fact in the universe. Vongola do use the 7 flames, yes, however there have been plenty of families that can use their own variant of flames. 

Though, if the invented flames are a problem I could remove them no problem. I kinda hope that I can keep the character design as it is, but if everyone is uncomfortable with the character I have no problem making adjustments.