The issue with the river is not just the health, it's also the trade, not needing boats. Also the extra bonus as a defender you get for people not having to fight over it. Finally, a particular favourite of mine in BtS is now you cannot use the levee.
The problem with your starting location is that you do have ivory indeed but what else have you got? 1 fish and 2 hills and 10 sea tiles, 2 of which only have 1 commerce. Then from what I can tell you have 5 grassland tiles- I dont think any of them are river placed so you have a very small cap placed on the amount of commerce generated.
Then the issue with the ivory is this (not sure if barbs are on) but not only do you have to build what could be a rather pointless galley earlier on to work the tiles but you also have to station some unit over there in order to guard it/keep a galley around to ship over. otherwise it may get pillaged on a regular basis.
I think in the future you should keep in mind switching your capital to a decent location because the current location is an average at best city, luckily to the south you have a load of trees and so if you have bronze/horses then you can chop out an army very fast and go and capture someone elses capital and use theres!
You shouldn't be afraid of moving your Settler in MP (As you weren't) but there has to be a point to doing so and not just blind moves (as you did with the second move on to the hill). Apologies if my post comes off a little harsh, it was not intended to at all
