I honestly thought those presets were from the "Legacy and Compatibility" soundsets, specifically "GarageBand 11 Sounds and Instruments" or one of the Jam Packs, but I can be wrong...
I actually have a newer test Mac that has Catalina with Logic 10.5 and I will have to test this... In the meantime, I went ahead and searched for the the Hybrid Morph Instrument and samples and this is where they are located for me... see screenshots below:
Hybrid Morph Instrument Location
( /Library/Application Support/GarageBand/Instrument Library/Sampler/Sampler Instruments//Hybrid Morph)
Hybrid Morph Samples Location
( /Library/Application Support/GarageBand/Instrument Library/Sampler/Sampler Files/Hybrid Synthesizers)
I would say give a try with downloading the Legacy and Compatibility soundsets from Logic's download Manager, let me know if that works, if not, I will test this on my Catalina Mac and report back.