1. To keep database backwards compatible - it can't be added to the current code thread - this does not mean that a separate db can't be done with modules,
2. do_set_mlock() requires no changes to allow it to mlock. The code is simple enough that it just needs to know what values and how to get them.
3. A copy of set_flood(), cs_set_flood() get_flood() and, cs_get_flood() need to be made that allows for anope to save the j to some where and allow do_set_mlock() to get the information back
4. unreal32.c would have to be modified to add j as a valid value in the CBMode myCbmodes[] and CBModeInfo myCbmodeinfos[] to handle the mode
5. One would also need to modify the *_clear commands to do +j since parameter modes are cleared separately from the mass modes. Less it would be the only mode not removed.
In short that is what you need to do to make it work.
Okay I need to stop looking at code cause if I don't I will rewrite cs_clear.c cause my ocd is kicking in...