actually, a partner can deduct unreimbursed partnership expenses (UPE) but only if the partner was required to pay the expense personally under the partnership agreement. there's even a line for this in Turbotax on the k-1 just below line 20Z. however, I agree that that's not the case here since this seems to be an expense that was incurred voluntarily and not required under the partnership agreement (if there even is one).
when possible I prefer taking bonus depreciation under 168(k) rather than 179. (had a partnership where the partners traded in their vehicles every 2 years and section 1031 applied back then - real pain with 179 recapture and refiguring basis). also no $ cost or income limits.
i also agree with the rest of your advice.
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