Oh, if you are staying only for a few days, and if those guys are working, then the only way to "meet up" would be for dinner, I guess. Then it's simply up to what you feel like :)
I don't know if this gives any good indication, but I am a Japanese female, and I made some "friends" right here on this Forum. Meaning, I found a few "regular" posters with questions that showed that they had genuine and sincere interests in Japan, and I decided to send them Messages in addition to posting my answers on the threads, which later led to direct e-mail exchanges. (Sorry I'm being anonymous this time.) Then when those guys came to visit Japan (they have been doing so), I decided to meet up with them in person. I had their full name, city/country they are from, general age range, gender (both male), marital status, but no photo or any more details. Of course they had similar information about me. Not connected on SNS yet then, so we had no photos of one another.
The first time I met up with them, well, I should say him, because I met them on separate occasions, it was together with my husband (English-speaking non-Japanese resident in Japan). We found each other to be trustworthy people, so from the second time on, it was me alone with the guy, going out to lunch or for an afternoon at a museum, garden, etc.
So... what's common is that it is in Japan, what's different is that you are the visitor meeting up with a Japanese guy, the reverse situation to mine. But if you are ok with meeting them in person at all, but have no real personal details, I would use the "usual caution," like not giving out your hotel name, not letting them come into your room, or not going to their home for dinner or whatsoever lol. But just because they are asking you out to dinner, I would not immediately associate that with their romantic interest and worry in that sense. Of course, if having to think about all this on your business trip is bothersome, you can always say oh you are too busy on this short business trip :)