I am presently still waiting for the specialized PCB drill set I ordered to arrive, as it is required in certain very tight spots around the outer traces, especially the speaker button.

However, in doing research for this there is, perhaps another potential alternative to drilling for transistor placement: The silver conductive ink pen, a product offered by MG Chemicals and others.

Below is a brief video demonstrating their use. Skip to 47 seconds to go by the ads and other unneeded info.

These pens can be a bit messy, as can be seen in the video, and I am not quite sure how well they work on top of the solder mask (so one might want to use the fiberglass pencil to remove also, in addition to the pads, the planned traces one wants to make with the pen).

In any case, in the end, the result might not be all that pretty, but I think it could be a viable alternative to drilling to make transistor connections.