1. The expense reports either literally killed him or perhaps caused some other negative termination like losing his job. There must have been something wrong with them, perhaps he was committing fraud, or perhaps he had too many difficult expense reports to process so his workload was too heavy?
2. 'Our deal' means the speaker had an agreement with the man that it was the speaker's responsibility to revive him, with the implication of 'up to me' that the speaker is the only one with that responsibility.
3. Your translation is correct, but to 'pimp something out' has a sub-meaning of excessive expensive decoration, possibly even in poor taste.
4. A crossbow range would be a dedicated outside area for practicing shooting a crossbow, as in archery. This would be a pretty unusual area to have, but he mentions a farmhouse so presumably he lives in a rural area with a large property, and likes to target practice with his crossbow.