For question (i) the seat 29J is free for all, and another status passenger could have it for free. Or someone can pay approx AUD90 to have that seat. The point would be that both categories of passengers could get a window or aisle seat for the same cost and avoid the middle seat. Indeed 29F is available for approx AUD 80, and the cheapest aisle seat is about AUD45, cheapest window AUD 55 - all prices assuming seat selection at the time of purchase, thereafter it gets more expensive. In other words it's unlikely anyone would select that seat unless the aircraft gets really full, there are both better and cheaper options available. On this route most passengers in WT would not have status, which is a key detail here.

Hence (ii) when we get to T-72, the majority of passengers won't have a seat selected, there is a good chance 29H will remain empty, it will then get blocked by TS. Ruby passengers are also unlikely to see 29H as available unless the aircraft is really full. Hence as long as there remains some unsold seats, there is a good chance that 29H will remain empty. If the aircraft gets full around 3 days out, another GCH will have access to that seat, but presumably would only select it if there really was no better option, or they were on such a tight schedule that they need a front seat to be able to get out quick - TS should keep some window and aisle seats available but they may be well down the back.

In short this shows how the dual combination of seat charging and Theoretical Seating can work well together, but if the flight gets full, as would be the norm from SYD on a Saturday, then you may find someone gets allocated 29J. The dynamic charges for seat selection, rising after initial booking, also discourages gaming seats, probably to the advantage of GCHs.