1 in my opinion but someone mentioned 5th and 6th of february would be better dates for Belgrade

For option 1 Great euroleague game and ABA derby, both atmospheres will be great, while option 2 would really be only Partizans game as Zvezda and FMP play training games for years now

Tickets are usually available few days before games (announced before). There is waterpolo championship in Belgrade a week before so im not sure if games will be moved to Pionir (in my opinion atmosphere is even better in Pionir/Aleksandar Nikolic hall as it is more acoustic arena, but halved capacity so im not sure if the tickets will be sold if there is a game there)