Batch compression in ffmpeg?

Question

fmpeg

Hi all. explain, please, ignorant ... because I don’t know where to turn, what forum ...
the essence of the problem: there is an audiobook, 200 mp3 files, with long file names, a bunch of meta tags, a picture inside each mp3 and a large bitrate. I tried to compress them in batch mode using ffmpeg.exe for a cell phone to mp3, but with a bitrate of 64 kb / s, removing all metadata to reduce the weight of mp3 like this:
for %%a in ("*.mp3") do ffmpeg.exe -i "%%a" -acodec libmp3lame -ab 64k -ar 44100 -map_metadata -1 -y "%%~na_.mp3"
turned out great, everything was compressed with high quality, all meta tags were removed, but there are two unresolved issues:
1. On a cell phone with a small screen, long filenames are annoying. how to set new short file names in ffmpeg during batch compression, even three digits is possible: 001.mp3, 002.mp3, etc.?
2. how to remove the image embedded in the original mp3 when batch compression in ffmpeg?
I would like to solve these two issues using ffmpeg.exe on the command line without using other programs, such as tag editors and renamers. thank you in advance.