I've done it exactly as you described with three of my four villages and they are all fine. The one village where I was trying to go for Tech points ended up having a few die from starvation (even though I left the game on 1/2 speed overnight) so I ended up buying Engineering 2 before Tech 2 so that they could build the dam and have crops (algae had occurred while I slept). So, I would do it your way.