Not sure, but generally, not all items are available on BR and even if they are available, they might be out of stock at that moment.

Combat jeeps appearing from the start seems to be general 1.13 issue at the moment. Those patrols you see moving around sporting that tank icon contain combat jeeps probably, there is no special icon just for jeeps. Tanks seem to "respect" ini settings about when should they appear in patrols, or at least I haven't seen a tank yet in those early patrols. Tanks might be able to appear earlier as part of counter attacks, so that might be it, if you took over all of Drassen.

Did you put an appropriate missile in your Bazooka? AFAIK, Bazooka is just a launcher, without "ammo" it is basicaly an expensive club there are some one shot launchers like LAWs that always come with a rocket inside and turn into trash when used, all other launchers need to be supplied with their rockets