[hamdani yusuf]

In Alice's frame, it would be translated to
1/γ=0.8
x'=0.75*0.8 = 0.6 light hours
t'=1.25*0.8 = 1 hours

Do I get the correct numbers?

I agree on the 1 hour, but the mirror then must have reflected the light after 30 minutes, and thus the (moving) mirror is 0.5 light hours away when it reflects the signal.

We can refer to Janus' diagram for crosschecking the result.
Is there anything wrong?

[Halc]

I agree on the 1 hour, but the mirror then must have reflected the light after 30 minutes, and thus the (moving) mirror is 0.5 light hours away when it reflects the signal.

We can refer to Janus' diagram for crosschecking the result.
Is there anything wrong?

No, his diagrams are usually spot on.
The Alice frame is the top middle one.  You notice the light reflecting the signal exactly halfway in that frame.

[hamdani yusuf]

The picture below shows the same situation, but I've added a mirror that's stationary in Alice's frame 1 light hour behind to make the situation more symmetrical. When Alice and Bob meets, they shine light to both mirrors.

Left picture is from Bob's frame while right picture is from Alice's frame
green=Alice's position
blue=Bob's position
red=Bob's mirror
purple=Alice's mirror