Several things to think about with this:
1: Flanagan would have to get clearance from the NRL to coach again (that ain't Earth shattering news).
2. Flanagan, if given permission, may have some restrictions put on his coaching.
3. Flanagan, I given permission, what salary would he be asking, or better still, what would the Dragons consider to be a decent offer given his background?
Looking at this in retrospect:
The Dragons may be waiting for some clarity from the NRL before making any move on Flanagan. That may be in the form of either assistant to McGregor, hence the clearing of the support staff McGregor currently has (Hornby etc), a return to coaching but only at CC level, hence the rumours surrounding Head, or ultimately as head coach, however, the restriction hear maybe in the form of an overseer such as Furner to keep him in check, hence also the move on of the current coaching staff.
The fact nothing has been said regarding the teams performance this year from senior management, could spell that they are in a waiting game regarding Flanagan and McGregor. Basically, how I read this is, if Flanagan is given the green light (or even an amber one) to return to coaching, we will move on that quickly. If Flanagan doesn't then McGregor is still signed as coach. So, really hedging bets here.
Another thing to consider is, if Flanagan has been seen in talks with Greenburg, then to me this indicates he has a job to return to, otherwise why else would he bother. There aren't many NRL coaching positions up for discussion only really Us, Cowboys and Warriors. The Knights position has been filled, Arthur looks more secure, Titans have a new coach, etc, and further, does he need NRL permission to coach overseas?
This may turn out to be another wild goose chase, but there are enough reasons to be optimistic imo.