1.Did you solve all the puzzles by yourself in all the games that you played and made W/T's for?
Usually, all the puzzles in the walkthroughs I write have been solved by me. There are some that got me stumped usually the arcadey ones. Jenny did the typing test for me on Nancy Drew Blackmoor Manor. The other puzzles I miss are usually due to time pressure (excuses, excuses).

If you see acknowledged names on the walkthroughs, they helped or added additonal information on the walkthrough.
2. Roughly how long does it take you to play through a game?
It really depends on the game and also my available time.
If I'm on time constraints: I play, write my notes while playing, repeat the chapter, rewrite my notes and then proceed to the next chapter. Then replay again. So, I don't know the length of time the game takes.
If I'm not on time constraints and I just play with no writing, a usual game is done in 4-8 hours. There are several games that took me long to play - Rhem 2 and Sacred Rings comes to mind.
3. Do you find them all easy or do you find many quite challenging?
I found Rhem 2 challenging. There will be individual puzzles that will put a brake on my gameplay and I need to stare at the monitor for a while.
4. Which games if any did you find hard?
Rhem 2.
5.What are some of your personal favourites?
It really depends on the type of game. I might enjoy a game because of the beauty, the puzzles, the fun, the dialogue but usually I enjoy logic games. In the games released in the last 6 months, I enjoyed The Awakened, Sacred Rings and Destination: Treasure Island.
6. Are you a teacher, professor, or have some qualification in logic?
I worked in medical allied field all my professional life. These include bench work, teaching, supervisory capacities and research-development in Hospitals, Medical Schools and Universities.