When should I choose "had come" over "came" in the following sentence?

Solution 1:

He had come would be correct, as that is past perfect—the timeframe of the past is the "I met Raschel", but by that time, Raschel had already come, so you want to go into the past even further, which is the past perfect tense, also known as the pluperfect tense.

As for held a meeting, paperrater.com marks it as a cliche. A cliche is a phrase that is overused a lot, but personally, I don't agree with it—the construction is perfectly fine to use. If, however, you really want to replace it, you could go with the shorter phrase "The board met and decided...".

Solution 2:

Both tenses are possible. With came, you present came and sent as a plain sequence of events, as in "I came, I saw, I conquered"; with had come, the had come sentence is presented as background information to the sent sentence. In either case, the first sentence precedes the second in time (this is how context works).

If you are going on about this meeting for a while, describing it in more detail, it would probably be more natural to present his coming as background information. However, even in that case, I have seen the past simple used in exactly the same way in works of literature, though it may sound a bit epic or affected; so you will not be alone. But my choice would be had come.