Confirmed that the two small parts are cable stops/guides for front derailleur. But I wasn't able to utilize them and received this answer "You can use either one" from Chris for my detailed questions and back and forth over the email. None of those nozzles fit tightly into the hole for cable.
Decided not to use those and hack something else to fit. From the local hardware store I bought 3 parts.

1. A rubber grommet.
2. A small flanged spacer
3. A slightly bigger flanged spacer than above.

The spacers are sized such that the smaller one inserts into bigger one and since both of them are flanged, my idea was to sandwich frame material between the two.
It worked perfectly.

Basically the larger spacer went into the hole from inside the frame with little circus and then I inserted the smaller one along with the rubber grommer into the bigger one which was now sticking out from the frame.

This created a nice tight guide for the cable and also closed any gap around the spacers.