In your opinion, do you think the Smith family would have been so prepared to reproduce those e-fits for the police if they had known Tannerman had most likely been identified & eliminated?
This is one of very many questions about the actions of the Smiths which can only be answered by, at best, an educated guess.
For example, why did it take 13 days to report their sighting?
Did Martin Smith honestly believe it was Gerry McCann he saw on Thursday 3 May?
Were the family really capable of drawing up those two detailed e-fits of different-looking men, one whole year after they'd only seen his partially-hidden face for a few seconds at most in the dark, and all told the police in Portimao on 26 May 2007 that they'd never be able to recognise him if they saw him again?
Why within the space of less than 4 months (Sep 07 to Jan 08) did Martin Smith switch from saying it was Gerry McCann he saw carrying away a child, to actively working with the McCann Team?
To answer your question, some time in early 2008 Martin Smith committed himself to the McCann cause, and has allowed the McCanns ever since early 2009 to make full use of the sighting as they saw fit - but without reproducing the efits.
I don't think it matters one whit whether Martin Smith knew or didn't know that Redwood was planning to say that Tannerman was actually Crecheman.
He is sticking to his story that he and his family really did see someone (dressed remarkably like Wojchiech Krokowski) with a child in pink pyjamas at about 10pm on 3 May - and that the man looked like two different men as revealed on the efits. He probably has no view on Tannerman/Smithman
It all seems deeply mysterious to me