The delayed triggered ability of Basri's second ability triggers if any nontoken creatures attack, and it counts how many nontoken creatures attacked. Attacking nontoken creatures that leave combat before the triggered ability resolves are counted. Token creatures that are attacking don't stop the ability from triggering and aren't counted.

Although the Soldiers are attacking creatures, they were never declared as attacking creatures. This means that abilities that trigger whenever a creature attacks won't trigger when the Soldiers enter the battlefield attacking.

The Soldier token created by Basri's last ability can't attack during the turn you create it unless it gains haste somehow.

Any effects that say that the Soldiers can't attack (such as that of Propaganda) affect only the declaration of attackers. They won't stop the Soldier tokens from entering the battlefield attacking.

You choose which player or planeswalker each Soldier token is attacking. They don't have to be attacking the same players or planeswalkers that the nontoken creatures are attacking, and they don't have to be attacking the same player or planeswalker as each other.