There are a lot of choices when playing prerecorded audio, but the main ones are:
1. File format (i.e. .wav, .mp3)
2. Bit Depth (i.e. 24 bit)
3. Sample Rate: (i.e. 44.1 kHz, 48kHz, 96kHz)
For file formats, its best to use lossless formats, like .wav or .aiff, rather than lossy formats like .mp3. If you have to use .mp3, try to use the highest bit rate (MP3 bit rate is a bit more complicated than sample rate/bit depth due to how the format works). 320kbps is recommended for mp3's, though 256kbps will still sound good.
You will likely be able to hear a difference if you use .wav vs .mp3 (with .wav being better), but it's not the kind of thing that will make/break a set. While I try to avoid playing .mp3s when playing on "big" systems, there are times this is the only format you can get, and I doubt much (if any) of the audience is paying attention to (or picking up on) a difference if it's a good song. The bigger issue I see are some tracks are mastered with a lowpass filter and you can hear the high frequencies disappear when mixing in/out. There's a tradeoff between file size and quality; when I DJ open format sets for mobile events and clubs, I often use 320kbps .mp3s for file size and availability. If I am DJing a producer set at a club or festival, I will use .wavs.
The best case would be to use 32-bit .wav files sampled at 96kHz. With that said, when I DJ, I am fine with 24 bit .wav files sampled at 44.1kHz. Keep in mind you can't "reincode" a file from a smaller bit depth or bit rate to a larger one. Most DJ players and mixers like the CDJ3000s, DJM A9 and V10, etc unify all audio processing to a max of 32bit/96kHz, so there's not a huge benefit to going over that. MK3 Series' DSPs are 64bits at 96kHz, so that will match or exceed the specifications on virtually all pro-level DJ gear. Keep in mind a sample rate of 40kHz would correspond to the Nyquist rate for human hearing, so for many, even 96kHz is overkill (though using an anti-aliasing filter and any oversampling could make this beneficial versus 44.1 or even 48kHz). Theoretically even a sample rate of 40kHz could perfectly reconstruct the original signal (assuming it is bandlimited to 20kHz).
What I would be more concerned about is quantization noise, as this will always be lossy. 24 bits should be enough to push quantization noise below the range of human hearing. To get the best possible sound from your BASSBOSS speakers, we recommend turning up the output gain of your mixer to push the sent signal far above the noise floor, and use as much of the bit depth of the speaker's DSP as possible. Just because you are playing a 24bit file doesn't mean the DSP in your loudspeaker is using all of those bits, so to best utilize the ADC, give the device a hot signal (without clipping or saturating, of course).
Some people have asked us about LUFS, and the target LUFS really depends. When I master, I try to get the LUFS as high as possible without the quality degrading too much, and find the -12 to -14 is a conservative range for that (even though I'd ideally aim for -12 or -14). In this sense, I'd tell producers to mix with their ears and not their eyes. I've had tracks come out around -7LUFS and others closer to -12 or -14LUFS. I think this really depends on the genre you are playing, and in my experience what matters more is consistency across different songs than the absolute number itself. Playing a -14LUFS song right after one at -9LUFS will sound like a huge difference. A lot of EDM is mastered to higher LUFS values (like -9), so I'd recommend producers try and match what songs they will be mixing in/out of, while paying attention to what sounds good.
AES recommends -16LUFS, but when it comes to what sounds best on a "big" system (without considering radio and streaming), it really does depend. If your range is -9 to -12, that's a good middle range and I wouldn't be concerned if it sounds good to you.
At the end of the day, what sounds good is good. My TL;DR advice would be to use a minimum of 24 bit .wav or .aiff at 44.1kHz, and a maximum of 32 bit .wav or .aiff at 96kHz if possible.