It's been a while since I've look at perfect competition and cost curves.
First off, it's helpful if you draw the standard diagram for a perfectly competitive firm, one with supernormal profits and the other with normal profits (and compare it to the 3 types of situations in Johns diagram)
From what I do remember, Long run equilibrium under perfect competition consists of:
1) P = MC = MR (profit maximisation)
2) P = Min ATC
Remembering that the market is the price maker, and the individual firm (johns farm) is the price taker.
In the long run, market price (indicated by demand and supply intersection) must be level with the lowest point on the LRATC curve (also lowest point on SRATC-2). This doesn't appear to be the case in these diagrams, thus it must be a short run equilibrium.
So in order to adjust to this long run equilibrium two things need to happen
1) Either demand for apples falls, or supply of apples rises in the market for apples. To bring about a price consistent with the long run equilibrium
2) John needs his ATC to move from SRATC-1 to SRATC-2. (Because any perfectly competitive firm not at its minimum LRATC will, in the LR, change its input combination to take advantage of lower average costs).
According to Johns apple farm, the firm is earning abnormal/supernormal profits because of the position of price on SRATC-1 i.e it is not the case that P=min ATC=AR. There is a distance between ATC (higher than minimum ATC on SRATC-1) and AR. This distance is abnormal profits.
If firms are able to make positive profits by moving outward on the LRATC curve, those profits will attract entrants into the industry in the usual fashion (shifting the supply cure outward). Profits will eventually dissipate to zero.
In the long run, a perfectly competitive firm is allocatively and productively efficient: P=MC & ATC=MC i.e lowest point on SRATC-2 and LRATC.
In regards to the high medium or low level of capital, because there are 3 options and 3 SRATC curves, I believe it is medium (greater than the quantity associated with SRATC-1, and lower that then quantity associated with SRATC-3).