Phil, I thought you were closing the hull on an earlier thread - this must be a new build start.

1: since you are writing about an inner stem I'll assume you are using an external stem. Since the strips are rather thin I prefer to shape the inner stem to fit the angle at which the strips meet, preserving the full strength of the strip to the very end. The outer stem covers the end grain of the strips, of course. The images shows how I go about shaping the inner stem, which I prefer to do on the bench. The hatched parts are to be removed and the lovely (IMHO) curves that result can be seen clearly.

Note A: in the unlikely event there is no external stem then the planks would be tapered to a pint so as to expose no end grain.

Note B: if the plans show something labelled a bearding line the design probably uses a single stem: you're meant to cut a rabbet of depth equal to plank thickness from this line tapering to zero depth at the rear surface of the stem. It's great if you have this information since if you modify it to use inner and outer stems by dividing along the bearding line the stem shaping is pretty obvious.

2: trimming the inner stem varies with design; check the plans which should show this information. I sometimes like to finish the stem with a prow or carrying handle, other times I carry the deck forward over the stem.

3: I can't help with the build sequence as I build boats different to everyone else it seems, but think ahead and picture how the job will proceed. Nick has a great book . . .