consider latex paint hates amonia. Fresh, dried latex paint will come up with windex that has amonia in it.
Many times latex will come up with warm soapy water and alittle scrubbing.
You might even try some baby oil.
Many chemicals will as you know remove latex but they are drying agents and will damage the leather, so what ever you choose to use, make sure its soapy or oily.
Try some saddle soap also, this might take care of it and nourish the leather.