The Wasmer repo's GitHub releases only include binaries for Linux, Windows, and MacOS, so that probably explains why linking didn't work correctly for Android.
Wasmer compiles to Android out of the box though, so it should be enough to compile your Rust crate with cargo ndk --target armeabi-v7a -o ./jniLibs build --release (or whatever architectures you want to target). At a previous company we built a library that used Wasmer under the hood and one of my coworkers integrated it an with native Android app, so this is definitely possible. You might need to check React Native's docs for how to link with native libraries to make sure you did everything correctly.