The identities of Gatland's support staff are due to be revealed at a press conference in Edinburgh next Wednesday.
And there has so far been no response from the Lions on potential roles for Farrell, Rowntree and Howley that were reported today by BBC Radio 5 Live.
There would appear to be no place though at this stage for Wales defence specialist Shaun Edwards.
Forwards specialist Rowntree and backs coach Howley were part of the 2009 Lions coaching team in South Africa, but it would be a debut for ex- rugby league star Farrell.
Howley worked as Wales' interim head coach for their opening autumn Tests against Argentina and Samoa last month, and he will resume that job for this season's RBS 6 Nations Championship while Wales chief Gatland concentrates full-time on Lions matters.
Howley (1997 and 2001) and Rowntree (2005) both toured with the Lions as players.
The Lions have not won a Test series since they toured South Africa 15 years ago.