This is my take on things
Red Dot city is the heavy production city. It is healthier than either of your selections because with a harbor built, you get extra health from each seafood resource. You have 2 already and crabs will give you +3. The river gives you +2. It also exchanges a grassland hills for a plains hill. Plus the coastal start makes harbors and Customs house available for increased trade route commerce. If you settle the commerce city to the north as you plan it meshes nicely. Blue Dot is where you would put it. Though i would use it for production of troops. Your two choices for your heavy production would share way too many tiles with your other city. You have plenty of farmable land so it's not like they would be wasted. The only problem with my choice is the three gorges dam/levee is not available there without a riverside location. You can build that in Blue dot if you need to, but with few production cities on this landmass, i would worry about it for a larger landmass with more cities. Your commerce cities should be in the heavily grassland areas to the south.
With minimal hills for your production cities, i would say Metal casting then guilds should be a priority after CoL for caste system. With guilds and caste system you get 4hammers for a plains workshop. That is the same as a mined plains hill.
Also, I would have used the first 2 fishing boats for the clams, since they give you twice the commerce. You are commerce poor this early and you will need it to since you are settling two production cities first.
I would settle redfirst and get that stone going and start the pyramids ASAP, Research sailing while you build the setteler for blue dot. lighthouse/greatlighthouse is the build order for blue dot. The great lighthouse is a HUGE wonder for maps like this. With a harbor and the great lighthouse coastal cities pay for themselves or come very close to it.
While the wonders build, settle 1 commerce coastal city north of red dot then one science city south of blue dot. All the while teching your way to CoL for caste system. Get a boat out there trying to meet new civs. If you can open up some overseas foreighn trade routes with the Great lighthouse you will have plenty of cash. Once you have CoL, either tech towards MC(possible colossus) for the workshops. and then either Lit or drama. If you want the great library in your capital, you should consider putting workshops on the floodplains temporarily. That is one advantage of the SE, you can change the tiles unlike towns which you have to keep as tiles and work forever.
for now.
