If you look at it like this, settle in place when the city is fully developed gains us at least 5 more river tiles. Now if as were philosophical we aim for a slightly more SE than CE we need to cottage the capital intensly.
Thus them extra 5 river tiles when fully developed will give us what 5 base commerce compared to the 2 we get from the sea throughout the game, so already we're making less than what we'd want. 25 to 10
Then add in the modifiers +1 for printing press +2 for free speech so thats then 40 to 10.
Thats all without being in bearo, even if you add colossus its still nothing in comparison. And not including the extra hammers you gain from universal suffrage.
Whilst 'city 2' with a worked would be able to perform the early function of a GP farm and possibly crank out a couple of GS's- say one for philo one for paper or similar.
On the subject of producing units, by the time we are producing units en-masse in the later ages we'd have what, 3 hills on the coast- going to be fairly heavy going if we're planning on just using that. Whilst we might lose slighlty on having a harbour it wont be much if we can establish reasonable land routes.
Free Speech and Bureaucracy are mutually exclusive. You assume we will be in those civics instead of Vassalage/Nationalism. Free Speech tends towards cultural victory, Bureaucracy only benefits one city. I'm sure our more warlike citizens would appreciate the extra support and exp of Vassalage, or the gunpowder army-raising capability of a draft in Nationalism (complete with happiness bonus from barracks and the espionage boost).
Moving 1 SE takes 1 grassland/forest, 1 silk/grassland/forest, 1 riverside grassland/forest, and 1 river corner plains/forest, and 3 unknown tiles out of the first city's radius. It gains 4 coast, 1 grassland, 1 dye/grassland, and 1 fish/coast...
We lose fresh water access, we gain an extra health from the fish, so health -1. Instead of adding one food to the river/hill, we add a hammer and a coin to the grassland the city is founded on... 1

+ 1

vs 1

+ 1

Moving 1 SE gains coastal access (ships, harbors, custom houses), effectively +1 extra

per trade route.
The fish can be connected faster than the pigs, and it won't stop growth in the process. The fish capital would benefit from a larger size earlier and therefore longer.
The silk and dye cancel each other out, and the forest on the silk will still be choppable for the cap. The same is true for the grassland exchange.
We have 3 unknowns, riverside forest/grassland, and river corner plains/forest vs 1 fish and 4 coast...
fish with workboats and lighthouse is 6

2

The riverside forest/grassland can be cottaged (2

6

), farmed (4

w/biology 1

), lumbermilled (2

3

1

), watermilled (2

2

3

), or workshopped (1

3

)
The fish can provide food for two specialists, so fish beats farm, fish beats lumbermill, fish beats watermill, fish beats workshop, and fish beats town without respect to civics.
3 unknowns 1 river corner plains/forest vs 4 coast....