I notice that library audio in FLAC format (44.1 kHz, 24 bits, mono or stereo) is in development : https://github.com/LMMS/assets/tree/master/Samples
It's good!!!

But one software, which I don't remember the name, ask you samplerate at the opening software before make music project.
So, here's my ideas :

-We could build samples recorded with all samplerates (44.1, 48, 88.2, 96 and 192 kHz) and in 24 or 32 bits.
-LMMS could be opened with choice of samplerate before make music project.
-The samples shown could be depending of samplerate (For example, you choose 96 kHz, so samples shown will be in 96 kHz only, but you could indicate to LMMS that you still want to import samples in 44,1 kHz. From internet for example.)
-Then, when you finished your project, you can export your project with choice of quantization, antialising, and audio format, but with samplerate already chosen at the beginning.

Have a good day!