Click the “Files” tab in Serato, therein bypassing Itunes completely. You would then just click & drag whatever files you wanted into a crate and work your way from there. It might help to maybe have either a copy of your songs or your “Dj tunes” (If you use a separate file format) in a folder specifically for it, so that you just have select the folder and import all the songs in one easy motion. It’s not the greatest thing of all time to use but it does exactly what you’re looking for, which sounds like you’re wanting to be selective about what you’re adding or taking away from your library. You can also just have them in a specific playlist, I’ve found that works well with iTunes as then it’s just Copy over the playlist to a crate and done. Just be aware that the meta data will change if you edit it in Serato, as it’s looking and editing the same data iTunes is. Unfortunately, as far as I know you can’t add album art through Serato, but MP3Tag is great for this & can even add missing Data.
If you’re working specifically in Apple’s formats, (AAC or AIFF/Aif) due to buying all your songs through Itunes, then I can’t help you (maybe). I stay from Apple’s formats as they’re limited in thier use outside of the Mac walled garden and I hate being tied to anyone thing except WAVs and FLAC. From my understanding though, they behave just like MP3s and Wavs, minus a couple differences. So maybe you can just follow the step above about sticking everything in a crate/playlist/folder and doing that? Or just add the files through the Serato files tab? (See above about Metadata changes) Itunes is a good library manager and meta data editor, but one thing I always felt like they needed was to have the option of Multiple libraries. But I digress.
AS for your laptop, are you able to meet Serato DJ’s requirements? (Not Intros) Back when I was using an i3 laptop, I would have that issue when I was doing large batches of music. There might also be corrupted data inside your music but in the case you stated and the corruption issue, Serato would just put a flag on it and move on unless the file is that bad.
Let us know how you get on and maybe we can figure it out if you’re still having issues. That’s what this forum is here for!