Actually these are very good! Not all of them are immediately obvious so some research/rewatching of certain scenes is required.

Here's my contribution:

1) What is the significance of John's blog counter being stuck on 1895?
I think it has to do with something about the canon, a poem or something like that. I've read it somewhere, but I can't fully remember right now.

2) What was the name of the cabbie in Study in Pink, and why?
Jeff (source: end credits for A Study in Pink, I don't remember it being mentioned in the episode, nor in the pilot).

3) Which line did Benedict lament as being poorly delivered in A Scandal in Belgravia? (source: commentary)
I really don't know, but I think I remember something about his response to Irene's "I would have you in this desk etc.". I think he said something like he should have answered her right away or something like that (without subtitles there are things I really don't get).

4) What was the key feature of Martin Freeman's audition that landed him the role?
What our Sherlock said: they saw he really matched Benedict and they had a great chemistry. I seem to have something about his sense of humour in the bottom of my head, but not sure about that...

5) Who has been replaced in A Scandal in Belgravia?
I don't know what you're referring to but... Sherlock's text alert?

6) What does HOUND stand for?
The names of the people involved in the experiment in Liberty, Indiana.

7) Page 15, Entry 1
Deadman

8) Where did Ian Monkford go?
I think it was Colombia.

9) What's John's theory about the rivalry between Mycroft and Sherlock?
That Mycroft nicked his Smurfs and broke his Action Men.

10) Who are the three directors who've worked on Sherlock, which episodes did they direct, and which of them had not worked with Moffat before?
As Sherlock already said: Paul McGuigan (ASIP, TGG, ASIB, THOB), Euros Lyn (TBB), Toby Haynes (TRF).

I would like to address the poem of which you speak.  It's called "221B" by Vincent Starett, one of the first and most famous Sherlockians.  You can google it if you would like to read the poem.  One can learn worlds of information by googling.

1) What is the significance of John's blog counter being stuck on 1895?
1895 was the year Sherlock was supposedly at his peak & a poem was written about it also.
221B
Here dwell together still two men of note
Who never lived and so can never die:
How very near they seem, yet how remote
That age before the world went all awry.
But still the game’s afoot for those with ears
Attuned to catch the distant view-halloo:
England is England yet, for all our fears–
Only those things the heart believes are true.

A yellow fog swirls past the window-pane
As night descends upon this fabled street:
A lonely hansom splashes through the rain,
The ghostly gas lamps fail at twenty feet.
Here, though the world explode, these two survive,
And it is always eighteen ninety-five.
– Vincent Starrett


2) What was the name of the cabbie in Study in Pink, and why?
Jeff Hope - this is a call back to a murdering cabbie in Study in Scarlett - Jefferson Hope

3) Which line did Benedict lament as being poorly delivered in A Scandal in Belgravia? (source: commentary)
"This is low tar."

4) What was the key feature of Martin Freeman's audition that landed him the role?
Moffat said '...the moment they put Martin with Benedict, it changed Benedict and the way he played the role. He was suddenly more like Sherlock Holmes'.

5) Who has been replaced in A Scandal in Belgravia?
Sarah was John's girlfriend in earlier shows, now she's been replaced by Jeannette, the boring English Teacher.

6) What does HOUND stand for?
The initials of the team members of the program being run at Baskerville:
Hansen
O’Mara
Uslowski
Nader
Dyson

7) Page 15, Entry 1
Deadman

8) Where did Ian Monkford go?
Columbia

9) What's John's theory about the rivalry between Mycroft and Sherlock?
Sibling rivalry : "nicked his Smurfs and broke his Action Man"

10) Who are the three directors who've worked on Sherlock, which episodes did they direct, and which of them had not worked with Moffat before?

Paul McGuigan - Study, Great Game , Scandal & Hound
Euros Lyn- Blind Banker
Toby Haynes - Reichenbach
Paul McGuigan hadn't worked with Moffat before, in fact hadn't done TV before! It was Sue Vertue who suggested him to hubby Steve; the other 2 have done Dr Who  shows so would have worked with Mr 'Dr Who' Moffat.

1.    What is the significance of John’s Blog counter being stuck on 1895?
Sherlockian in-joke that says it's always 1895. I didn't know about the poem before - thanks!
2.    What was the name of the cabbie character in Study in Pink, and why?
Jeff Hope – name of the original murderer in A Study in Scarlet was Jefferson Hope
3.    Which line did Benedict lament as being poorly delivered in A Scandal in Belgravia (from commentary)
This is low tar (emphasis on low rather than tar)
4.    What was the key feature of Martin Freeman’s audition that landed him the role?
The dynamic between Martin and Benedict enhanced the way Benedict played Sherlock
5.    Who has been replaced in A Scandal in Belgravia?
The aunt’s ashes
6.    What does HOUND stand for?
Leonard Hansen, Jack O’Mara, Mary Uslowski, Rick Nader and Elaine Dyson
7.    Page 15, Entry 1
Deadmans Lane
8.    Where did Ian Monkford go?
Columbia – The Great Game
9.    What’s John’s theory about the rivalry between Mycroft and Sherlock?
Nicked all his Smurfs…broke his action man.
10.    There are three directors who’ve worked on the 6 episodes of Sherlock. Who are they, which episodes did they direct, and which director had not worked with Moffat before?
Paul McGuigan – A Study in Pink, The Great Game, A Scandal in Belgravia and The Hounds of Baskerville. Paul McGuigan had not worked with Moffat before.
Euros Lyn – directed The Blind Banker. Has directed three of Moffat’s Doctor Who episodes.
Toby Haynes – directed The Reichenbach Fall. Has directed five of Moffat’s Doctor Who episodes.

Kazza got the most correct answers!

Yeah. He says "I know she's been replaced". It was a bit cryptic...but cryptic can be fun. Especially when you know the answer lol.

No-one notice that Moffat always uses a 'Jeff' in his shows?

Jeff from 'Coupling', Jeff from 'The Eleventh Hour', Santa's called Jeff (Apparently), There's a David Jefford in both 'Press Gang' and 'Chalk' and a fluttering of Jeffs throughout his work.

I thought the lack of mentioning the cab driver's name within the show was a nod to the fact he usually always tries to. Probably me just over thinking things.

Great quiz! Who is up for the next one?

-m0r

It would seem by reply etiquette that it's me you're referring to...

I will put something together but it wouldn't be for this week. Perhaps next week!

-m0r

Yeah that's fine - we can wait till next week!