This is an interesting problem you are raising. However, I wonder whether you are approaching it from the right direction.
The important thing, surely, is that your intentions and thoughts are accurately presented rather than that every word is rendered in the translation. For instance, your example "They will be crossing the equator on Tuesday." How, in every essential, does that differ from "They will cross the equator on Tuesday"?
English is a largely uninflected language, instead of having word endings to convey meanings as French does, English uses additional words. This is due to English's germanic origins. The arrival of the Normans added different structures. In consequence, by mixing the two language systems, English sometimes presents a flexibility which French does not possess.
Rather than translating the words, why don't you translate the idea?
I'm sorry if this sounds like preaching, that's not my intention, I'm just suggesting a different approach to your problem.