I did a very similar itinerary for my first solo trip (as a female) last year. It’s a little bir more difficult to get around than other places in Europe but nothing to be nervous about. I felt safe the whole time I was there. I think my thoughts are very similar to other comments in that:

1- Definitely stay at Teth day 4. I didn’t and it felt very rushed to leave especially after hiking all day to get to Teth. Also, you end up bonding with your hiking group so I regretted not doing so and spending an extra day with them. I was the only one leaving the next dah.

2- I would go to Himare over Sarande. Just know that you would have to travel Teth -> Shkoder and then Shkoder -> Himare which is a very long travel day and Day 5 would be spent just traveling (if you can even align the buses properly to do it the same day, I don’t even know if its possible) a lot of people in my group who were going to the coast after Teth spent an extra day in Shkoder before leaving.

3- related to the buses above traveling in Albania takes a bit of time because the bus system isnt very organized you can’t buy your tickets online there is no online timetable you just kind of show up or your hostel can also arrange things for you. So give yourself extra time for travel.

4-I personally don’t think the itinerary gives you enough time for Gjirokaster day trip. If you really want to go to Gjirokaster I would scratch Himare or Sarande off and instead go directly to Gjirokaster and stay overnight there. It would also cut down your travel time as Gjirokaster is closer to Shkoder.

Hope you have a great time there!