For introduces verse 15 as the cause of 2.14b.

The pronoun we, as in verse 14, probably does not include the readers.

The aroma of Christ is figurative language (so Good News Translation says “we are like”), comparing Paul’s ministry to the sweet smell that burnt offerings gave off to God. This is similar to the figurative use of “fragrance” in the previous verse. The word used here is different, but in this context the two words are practically synonymous and may have to be translated the same. The difference is that here the good odor is offered by Christ to God.

Of Christ may be translated as “offered by Christ” (Good News Translation, Revised English Bible).

Those who are being saved … perishing: see 1 Cor 1.18, where the same expression occurs. Good News Translation‘s “lost” does not refer to people who are losing their way but to people who are on their way to destruction. The participles used in Greek are present passive. The present tense should be preserved in the receptor language, but in some cases the passive forms will have to be translated actively: “those whom God is saving” and “those who have no hope [of salvation],” “those who are on the road to destruction,” or possibly in a negative way, “those whom God is not saving.”

Quoted with permission from Omanson, Roger L. and Ellingworth, Paul. A Handbook on Paul’s Second Letter to the Corinthians. (UBS Handbook Series). New York: UBS, 1993. For this and other handbooks for translators see here .