(Linux/Mac) find command - how to execute multiple commands to the same file before moving on to the next one?

Edit: My shell version is requested: zsh 5.7.1 (x86_64-apple-darwin18.2.0)

I'm on Mac, but this is a Linux command (find) I'm using in terminal.

So my overall goal is already somewhat reached, but I'm wanting to make it cleaner/more efficient and have less problems.

I'm converting a bunch of .wav and .aif files in several sorted directories to .flac using:

find . -type f -name "*.aiff" -exec flac -8 "{}" \; && find . -type f -name "*.aiff" -exec rm "{}" \; && find . -type f -name "*.wav" -exec flac -8 "{}" \; && find . -type f -name "*.wav" -exec rm "{}" \; (convert.sh)

Which works, if I'm not continuing work in the directory. Doing so produces more .wav and .aif files that end up being deleted without being converted since I produce them during conversion, and find isn't looking for more wavs to convert after the first part of code is executed, only for wavs to delete.

I've tried using && with find - for example: find . -type f -name "*.wav" -exec flac -8 "{}" && rm "{}" \; However that seems to think after && is a new command, not part of the same command I want to execute, and gives error find: -exec: no terminating ";" or "+".

(Potential Solution) I know I could somehow use a .sh file but I don't know how to set it up so that it works like /path/to/convertanddeletebeforenextfile.sh /path/to/filetoconvert.wav to be able to use find . -type f -name "*.wav" -exec /path/to/convertanddeletebeforenextfile.sh "{}" \;

Could someone help me with this final straight to the point goal:

Convert .wav/.aif to .flac and delete original, then move to next .wav/.aif