Deleting edge loops is a good start. You can also try retopologizing the mesh. I know Maya has some built in tools for this, but I’ve been using Topogun 2 for characters and it’s great!
If good topology doesn’t matter(and since wouldn’t be an animated mesh it probably doesn’t) you can try Maya’s built in Reduce feature. Honestly I’ve never gotten a great result out of it, but it’s at least worth a try. You can find feature by clicking “Mesh>Reduce(click the box next to it for more options)” and it will ask you for a target poly count. It’ll do it’s best to reach that polycount and maintain the volume of the model.
As you’ve mentioned, once you have the low poly model you’re going to want to project normal maps from the higher poly model to the lower poly model. You can get a ton of detail back with method and it maintains a cheap rendering cost. Maya can do too in the rendering menu. Just google “baking transfer maps maya” and that should point you in the right direction.