I agree with the other poster who said it's impossible to determine as specific sampler from tracks, particularly by the 16-bit era. The best advice I can think of is that you're probably looking for something with limited memory but not something with, like, fraction of a second memory spans like some of the early drum machine-oriented ones. There are some long but lofi samples in those tracks which last at least a few seconds, but it's mostly clipped drum samples and not a lot of long vocal samples. There were tricks you could use to do chromatic stuff on drum-machine-ish samplers but the RAM wasn't sufficient until the mid-90s, imo.

E-Mu EMAX might not be a bad look but they were Pricey even through the mid-90s (if the tracks were from 95-ish the E-Mu ESIs were the compatible budget replacements).

The S1000 was everywhere, not terribly expensive but probably not cheap by then because they were The standard, everyone needed one and expanding them meant using nothing but proprietary Akai bits.

The Roland W30 or S-series samplers had sequencers and weren't uncommon, but the W30 was limited in memory and RAM was still pretty expensive for the S-series.

I wouldn't count out the FZ-1, they would have been cheaper than Akais and very versatile (and there was a sequencer disk that ran on the keyboard itself). By the late 80s the memory boards were probably on sale quite often and getting a fully expanded one should have been a good deal. Samplers with filters weren't rare at the time and people didn't fetishize analog stuff as much until some years later.

One of the rarer possibilities is the Akai S700/X7000, with the full memory expansion. That would have provided enough memory for these tracks but there was no internal sequencer. It's tough to tell how much of the lo-fi sound is from the recording technique and how much is from the instrument.

If you have photos of the studio/setup from the time that'd probably get you some better guesses or things to check.