This was a fascinating problem and just demonstrates the incredible complexity of the full BtS game. Even with such a simple premise as an entirely grassland map the number of difficult decisions and awkward questions that are hard to answer was manifold.
Obviously each city is limited to 2 food and 1 hammer from its city tile. Health was the initial limit on growth and only the aquaduct and Hanging Gardens can suppliment it in the early game and with low production they are difficult and expensive to gain.
Cottages: are the obvious solution to commerce needs. But getting more than a few per city is tough. At 2 health a cottage city can only grow to size 4 and produce about 16 commerce and 1 hammer. A basic strategy is beeline Liberalism, Printing Press and Democracy to turn towns into powerhouses.
Granary: Did people build a granary in all their cities? If you whip at the health cap the 2 food is effectively worth about 1 food = 1.2 hammers without a granary for a total of about 3.5 with the city tile hammer. With a granary this becomes 6 hammers per turn and is quite good for churning out archers or longbowmen whipping 1 time every 10 turns or so.
Settlers: What is the best way to build settlers? A size 1 city can build one in 34 turns and work a cottage. But grow the city to size 2 (takes 11 turns) and then build a settler and you can whip once 72 hammers have been put into it. That takes 24 turns and together allows 2 cottages to be worked while the settler is being built. Are there better ways to build settlers in the early game?
Workshops: Initially very weak and not worthwhile, with Guilds and Caste System they can become quite powerful giving a size 2 city working 2 workshops gives 7 hammers which seems very powerful compared with what has gone before. That can churn out Protective archers in 4 turns and longbows in 7 turns; trebuchets take 11 or 12 turns and camel archers take 13 turns.
Religions: These provide culture and replace monuments. OR is a very powerful boost to building and wonder production if combined with Slavery or workshops. A temple allows a priest to be run at size 2 and it takes 34 turns to produce the first Great Prophet. What do you use that for? Settle for 2 hammers and 5 gold or make a shrine whch gives a small amount of gold and 1 GPP? Usually I would go with the shrine but here with so many cottage cities gold is much less useful than hammers.
Pacifism can be very useful for boosting GPP production for a short time.
Courthouses: Did people build these? They certainly were not a priority for me since the 120 hammers could be used other ways. My cities were tightly packed so distance was never a real problem and cottages paid all the bills. The AIs were backward and there seemed no use for the free EPs.
Pyramids: Very hard to build but potentially gamebreaking. Three civics are of use.
a) Representation is not needed for happiness and the extra 3 beakers is weak since there are few specialists.
b) Universal Sufferage allows towns an extra hammer and rush buying at 3 gold per hammer. There are a host of sub strategies using early US from Pyramids too numerable to mention.
c) Police State can provide an invaluable 25% boost to hammers from workshops or Slavery used to build units for a final push
Apolostolic Palace: A very powerful wonder when combined with temples and monasteries of the state religion. Gamebreaking if it can be built early enough.
Hanging Gardens: Provides an extra health and allows all cities to grow 1 bigger. This caused the welcome problem

of unhappiness in my cities which was solved by whipping a temple.
Other wonders: Did people build any other wonders? Stonhenge was useful for me giving extra culture and a continuous source of 2 GPPs and was cheap enough to kickstart in the capital with Bureaucracy and OR. A settled GP was a powerful source of extra hammers.
Forges: The extra unhealth means these reduce maximum city size by 1 pop. This could be worth it in a few production cities to help with whipping or workshops once an aquaduct is built. Running an engineer at size 1 could be a way to get a GE to build any wonders with Pacifism this should not take long if other GPs have not already been built.
Thanks VoU.
This was a useful learning exercise for me. The simple combination of low food and hammers with high commerce showed the limitation of granaries and courthouses in these special circumstances. I am a strong advocate of both these buildings in normal games. It was refreshing to see their weaknesses.