Первый находится на пристани, напротив президентского дворца, второй в северной части города. С Вашим опытом, вряд ли можно заблудиться! Удачи! ))

As far as I know yes.

The tram stop is is called "Hakaniemi", right next to the square. Trams 1, 1A, 3, 6, 7A, 7B, and 9. There are also buses and a stop of the metro line.

Normally on 24th of December every placd will be closing early than normally. Some supermarkets will be open of course. Most of Christmas markets are not open. Museums will be closed. You may check also Visit Helsinki website or Helsinki Tourist Information

All this could be avoided if only TA would accept my suggestion of listing "Kauppatori" (the famous market) as "Kauppatori (Market Square)". They seem to have turned down my request for them to do so. People see the listing "Hakaniemi Market Square" and assume that this latter is the famous one by the harbour that they have visited. I don't think much of the market at Hakaniemi, but I prefer the indoor market there. That's not to say I don't like Kauppatori, but it is a completely different experience and a different place.

market has about 10 stalls and that is that. You need to go to the Kauppatori Market, not this one. On the other hand, the Market Hall at Hakaniemi is better (cheaper and better quality goods and stalls) than the Vanha Kauppahalli (Old Market Hall) at Kauppatori. So you need Kauppatori for the outdoor market experience and Hakaniemi for he indoor one. Don't get them mixed up as the majority of people do!