Can I play diatonic harmonica tab using tremolo harmonica?
It depnds on the model. If you use a 40 reed tremolo harmonica it works. Just combine 4 of the little holes to one “channel”. This imaginary channel produces the same notes a 10 hole diatonic harmonica does and you can play any tab.
Yes you can however you cannot bend the reeds on a Tremolo harmonica. I assume you are playing a richter tuned Trem and not a solo tuned or Asian/Celtic tuned Trem
I say this because most Asian Trems and the Ocean Star Trem are tuned differently. You can get the I Chord on the blow of the lower register but the V chord is absent unless you use a partial chord. You can play melodies on the lower register of the Asian/Celtic Trems but cannot on the Richter tuned Trems. You do however get those fantastic chords which they were made to do on the Richter tuned Trems and the melodies can be played up on the higher registers.
So don’t get them mixed up when looking for tabs. There are indeed tabs for Tremolo but in your case you asked if you can use diatonic tabs and the answer is - yes. You can take Richards advice and use a 40 reed Trem but you are just a little restricted in the songs that you can play as you cannot perform bending and melodies on the lower register but when you research the web for songs you have plenty to work with and there are some great players out there.
Bottom line: Know how your Trem is tuned and use the correct tabs accordingly. You can also transpose a lot to the upper register. Most importantly - HAVE FUN!