Welcome to the fun…
I usually rack to secondary off the lees after the initial turbulent primary fermentation has settled, then leave it for a few weeks or even longer to clear and mature. However, this is optional. You may well find the harshness of fully fermented cider goes away after a few months as it matures and you don’t really need to add any sweetness.
As
@jnesselrode suggests, pasteurisation really isn’t scary if you follow the “rules” (i.e. keep carbonation and temperature as low as possible). Use the search function at the top RHS to search my various posts on this.
As far as “appleness” is concerned, let me paraphrase Andrew Lea (Craft Cider Making)… “wine doesn’t taste like grapes, nor beer like barley, cider is cider”.
Apple juice is roughly 80% water, 15% sugar and 5% flavour compounds. The unique flavour of cider comes from these flavour compounds in the way they are affected by fermentation. Adding AJ or AJC after fermentation can enhance these as well as provide sugar for sweetness and carbonation.
For carbonation, I take a slightly different approach to adding a certain amount of sugar. I add sugar (or AJ or AJC) to the bottling bucket to increase the SG by two gravity points per volume of CO2 required (i.e. for 2 volumes, increase SG by 0.004) and bottle. If a sweetened cider is the target, then increase the SG further and pasteurise once the two volumes CO2 has developed.
As a simple example, for say 10g/L sweetness (about the same as ½ tsp of sugar in a cup of coffee), add sugar to 1.004 for carbonation then another 0.005 for sweetness for a total SG of 1.009. Ferment the 0.004 for CO2 and pasteurise at 1.005 leaving the 0.005 for sweetness. Of course, you can do all of this “on the way down” but it is a bit harder to get right so simply adding to fully fermented SG 1.000 cider is the easiest way.
A word of caution when using the plastic bottle squeeze test for monitoring carbonation. Firm is firm (i.e. the bottle will be firm at above 2 volumes of CO2 and will still feel much the same at 5 volumes of CO2, so monitor and pasteurise once the bottle is firm otherwise potential BOOM!). A simple alternative (and check) is to open a bottle every now and then to see how carbonation is progressing… plus you can drink it in the interest of research!!
I hope this helps… enjoy the journey!