That's an odd thing to say.
Why odd? He does avoid lying. Even his writer calls him "a liar who doesn't lie". That doesn't mean he never does it 
Kinda like me - I generally try not to lie, since I'm awful at it. Doesn't mean that I don't always um... modify the truth in my favor 
That, and the claim that he'd lived as a wandering apostate most of his life while it was just for one year.
Actually, he never directly said that - that part is simply assumed and he does little to correct it.
Besides - we don't know how much time he spent as an equivalent of a wandering apostate (apostate is, by dictionary definition, a person who renounces a religious or political belief or principle - and considering that he was a leader of a rebellion that was aimed at overthrowing false gods, we can pretty much safely say that Fen'Harel was pretty much almost always an apostate, despite the definition of the word in current Thedas shifting slightly) during time of Elvenhan; we do know however that Evanuris did warn the People that "the Dread Wolf comes in humble guises, a wanderer who knows much of the People and their spirits."
So when Cassandra asks "Solas, have you always lived alone? Out in the wilderness, as an apostate?" and he answers "For the most part" you can either assume that he says "for the most part in Veiled world", or you can actually interpret it as an insight of how his life indeed looked like.
I mean, we do know that he was involved in some sort of grand war and that he apparently served as a guardian for Mythal, but we can't yet assume that it was most of his life. It might be that after the job was done and he helped the Evanuris, he might have been let go of his obligations and indeed spent most of his time wandering and learning of the Fade, only to come back to the civilization and see how much wrong happened since he left, or perhaps shifted his perspective or maybe found no other solution other than rebellion to overthrow the Evanuris.
Or we can assume that the "wilderness" was indeed the Fade and he spend most of his life studying it. Neither would really be a lie, especially if you consider the symbolism of his Hermit tarot card.
He does tell a bald-faced lie the first time you encounter veil-fire, saying he has never seen it before.
That's not a lie. I mean, the Veil-fire is called the VEIL-fire! It means that it's something connected to the Veil - and Solas never personally saw the Veiled world prior to him waking up, so by extension he likely never physically saw the Veil-fire prior to that. That doesn't mean that the Veil-fire isn't technically something that originated form a similar spell, but it is apparently a distinct new invention, created after the Veil has shrouded the world.
I think they're talking about the Temple of Fen'Harel in Trespasser, which is brimming with veilfire and requires it to solve several puzzles and proceed with the game.
Aside form the fact that it may not be technically Veilfire (how can ancient elves call something VEIL-fire prior to the Veil? Or how could be memory of a fire lit where the Veil is thin before the Veil had existed??), who said that the temple was left exactly in a state Fen'Harel left it? We do know that many ancient elves have survived the creation of the Veil - and they might as well used his sanctuary after the collapse of the civilization, maybe even transforming into some form of a cult (I mean, aside from the fact that we do know that there were/are still people working for him even prior to the collapse, i.e. Felassan, who likely didn't spend so much time in uthenera as their exhausted leader).
They might have lit the Veilfire, just like the elves who got trapped in Vir Dirthara (and we know that they did) might have crafted the Veilfire out of an older spell, perhaps in order to try and escape the library.
I'm thinking, "growing up in a small village to the north", whilst vague is still probably far enough from the truth that you could call it a lie. Although as I type this I realise I think it's a lie because I subscribe to the theory that Solas was a spirit before. So I may be completely wrong about that. And Solas may also be talking in metaphors. Who knows hehe.
I don't see how "growing up in a small village" is incongruous with him being a spirit before - I mean, he distinctly tells us that he grew up in a small village, not that he was technically born in it (though even if he didn't, that doesn't negate his origin as a spirit as well... especially given that everyone might have originated that way, even if they don't remember it).
He does tell Sera that "we were all young once", so it can be safely assumed that those spirits that manifested outside of the Fade need some time to do some growing up. If anything, that suggest that he might not have just been forcefully yanked from the Fade by Mythal, but she convinced him to manifest from the Fade and gave him some time to adjust.
Also... look at Cole. He might have not been 'born' in a traditional way, or anywhere near Inquisition, I'm pretty sure he can legitimately say that he did partially grew up in Skyhold.