I visited a few years ago and took the tram once. The newer 8101-model trams have a lowered floor and ramp, but not every tram stop is accessible since the platform is very narrow and there isn’t room to lower the ramp etc.
The city website says the following stops are accessible:
- Yunokawa
- Keibajo-Mae
- Goryokaku-Koen-Mae
- Chuobyoin-Mae
- Chiyogadai
- Showabashi
- Matsukazecho
- Hakodateeki-Mae
- Shiyakusho-Mae
- Uoichibadori
- Jujigai
- Houraicho
- Yachigashira
Which is actually most of the stops. (Though, remember that even if the stop is accessible, only 8101-model trams are accessible, so you might need to wait for an accessible tram.)
The only thing I could find about buses was a public report from the city from about 9 years ago that said about about 50-60% of the buses were accessible and they are aiming for 70% in the next 4 years (so, 5 years ago)…