Are there direct replacements for BC549 and BC559?

Just look at how the type number is composed. "BC549" is the basic type number, "C" is the current gain classification, "TA" stands for the way they are packaged (taped or bulk, "T" probably stands for taped, "A" for ammo pack) and possibly if the part has straight or kinked leads. But usually, bulk parts have straight leads (they cannot be taped) and taped parts have kinked leads to bring the leads in a straight line at 100 mil spacing.

If the schematic doesn't specify the current gain classification (it just says "BC549") than most probably anything will work. If you have a specific PCB, check the footprint. If the pads are in a triangle, go for the straight lead variant, if they are in a line, the kinked variant fits best.