While it's all fine and dandy to claim that "Lanun actually gets an advantage since they get good coastal cities" you might want to consider the downside - they practically cannot build cities inland, due to farms being useless for them.
Now, I play FfH mainly as multiplayer, so for me this discussion is more about wanting to play a balanced sea-oriented game as Lanun, while still having a decent chance while playing Pangaea or large continents-map.
It's also notable that building merely coastal cities will end up having very large distances between cities which very quickly adds up as enormous upkeep costs.
Yet another issue is that while land-based civilizations keep improving their buildings (Sanitation, Commune with Nature), Lanun gets nothing after Sailing. The +1 food from Lighthouse is more of a deterrent than advantage, since it is a must to build to every city in order to have competitive cities EVEN ON COAST.
So, while others are building up their empire, Lanun gets to spend 20-30 turns on building a lighthouse in every startup city. Now, after Lighthouse is built, the Conquest solves many of the building issues - except that when you compare the outputs to other civs, they are still getting more for that civic with farms.
All in all, Lanun have an advatage over others only in the beginning, and only if they have decent shoreline to build to (decent = at least 6 workable ocean squares). With agriculture, everybody surpasses the lanun in food production, and with sanitation the advantage that Lanun got from their Lighthouses vanishes. In addition to this, Lanun starts some 700rp behind everybody since they had to get Sailing. And yes, they need to get Fishing as well in order to even produce anything on the sea.
What Lanun would need is basically getting that another +1 food from some tech, be it Astronomy, or building -say Pirate Harbor - to keep them at par with the advances of other civilizations.