It just gets better and better!
Blair, firstly and most importantly happy birthday!
Secondly, your opinion on the current election matters... I am a little sceptical as to 1. Why Turnbull ceased counting of the votes till the Tuesday and 2. At the fact that there were supposed to be a number of probable ALP seats in the seats still in doubt when the counting stopped and now miraculously they have disappeared and everythings going to the Libs. Or is this how it was always going to play out with those seats?
No conspiracies here, and Malcolm Turnbull doesn't have anything to do with it - the AEC takes its independence very seriously (I've heard it said semi-seriously by Americans familiar with Australia that the US should outsource the running of their elections to the AEC).
There's never been much counting of new votes on the Sunday or Monday - these are usually devoted to transporting absentee and pre-poll votes cast outside their home electorates back to home base, and rechecking votes cast on the day (as well as giving the staff a bit of a chance to get some sleep after working 16-hour days on the Saturday). Normally the only new votes which get added on the Sunday/Monday are those from 'mobile' teams, which in city seats normally means hospitals and nursing homes (in outback seats these also take in Aboriginal communities).
On average, nationally, the Coalition does about 5% better amongst postal voters than they do amongst ordinary votes (absentee and pre-poll votes are much closer to the average). This used to be attributed to Liberal voters being richer and more likely to be travelling, but I think these days it's more about postal voters being disproportionately elderly in a normal election. (One of the unknowns in this election is whether, with the election being in school holidays in most states, the demographics of postal voters will be significantly different to usual - in Victorian state elections, which are in late November after the end of uni and Year 12 exams, postal and pre-poll voters skew younger, to the advantage of Labor and especially the Greens).
It so happens that three of the doubtful seats, Flynn, Capricornia and Herbert, are seats where the Coalition has a history of doing particularly well on postal votes (in Flynn last time, they did 12% better than they did on ordinary votes). In Flynn and Capricornia, this is because these seats consist of a strong Labor-voting town (Gladstone and Rockhampton respectively) and a strongly conservative hinterland, and the postal votes come disproportionately from the country. In Herbert, it's because a lot of military personnel deployed overseas vote there because Townsville is their home base. Antony Green's projections factor all of this in, which is why his projections sometimes differ from the current results.
Conversely, Hindmarsh is a seat where Labor tend to do better than average on postals, which is why Labor's more confident there than they are in the Queensland seats even though their current lead is narrower. Anecdotally, one explanation I've heard is that Hindmarsh has a significant community of Greek-Australian retirees who spend the southern winter in Greece, and mostly support Labor (it doesn't hurt that the Labor candidate is of Greek ancestry).
Not sure if it's truth or truism but in NZ it's normally expected for special votes to trend left. To the point that the greens will gain or nearly gain list seats between election night and final count. Think it's to do with the high proportion of liberal young kiwis living overseas or in no fixed location domestically at any given time.
Question: why is it easier for minor/fringe parties to win senate seats compared to whatever you call the main house. I think I'm looking more for a political answer, ie if there's a particular theory or philosophy behind why this should be the case, rather than an explanation of the mechanics
The mechanics is the main reason - the Senate has proportional representation (parallels to the list vote in NZ, although the details of the system are quite different), whereas the House has single-member electorates (with preferential voting). This means that in about 90% of seats, there's little point in voting for a minor party or independent since they have little chance of winning (and a lot of minor parties that run in the Senate in most or all states run candidates in few, or no, House seats), whereas (despite some changes to the system since the 2013 election) there's every chance of getting elected with 4% or so of the vote in a state in the Senate. In turn this provides voters with more incentive to vote for a minor party in the Senate (especially if their preferred minor party isn't running in their seat).
In 2013, parties other than Labor, Liberal/National and the Greens got 12.4% of the vote in the House and 23.4% in the Senate. I can't yet find aggregated national progress results for the 2016 Senate but would expect fairly similar numbers this time round.
Not sure if it's the mechanics or many Aussies' stubborn determination not to give both their votes to the same mob. I've always voted ALP in the House of Reps but my Senate vote has been Greens at the previous 4 or 5 elections, until this year I went for the Australian Cyclists Party.