Make a 32-bit FileMaker 14 application

One way is to simply remove 64-bit code from FileMaker. If you run in terminal the file command, you see that FileMaker 14 is a 32-bit and 64-bit universal binary:
Now to make it a 32-bit only app, run the following command (one line):file ./FileMaker\ Pro\ Advanced.app/Contents/MacOS/FileMaker\ Pro
./FileMaker Pro Advanced.app/Contents/MacOS/FileMaker Pro: Mach-O universal binary with 2 architectures
./FileMaker Pro Advanced.app/Contents/MacOS/FileMaker Pro (for architecture x86_64): Mach-O 64-bit executable x86_64
./FileMaker Pro Advanced.app/Contents/MacOS/FileMaker Pro (for architecture i386): Mach-O executable i386
This removed 64-bit code and you now have a 32-bit only app:lipo -thin i386 ./FileMaker\ Pro\ Advanced.app/Contents/MacOS/FileMaker\ Pro -output ./FileMaker\ Pro\ Advanced.app/Contents/MacOS/FileMaker\ Pro
For relative paths to work as above, you need to move in the right folder using cd command in Terminal. Please also make a backup and be aware that any updater will probably restore the app.file ./FileMaker\ Pro\ Advanced.app/Contents/MacOS/FileMaker\ Pro
./FileMaker Pro Advanced.app/Contents/MacOS/FileMaker Pro: Mach-O executable i386
PS: Do at your own risk. If something goes wrong you need to reinstall FileMaker 14.