Do not overlook cash needed at completion. Two offers can have similar long-run costs but very different upfront demands. If paying the arrangement fee reduces your available buffer after purchasing a MX$25,650,000 property, that may matter more than a small monthly saving.
I’d be cautious about justifying the offer with a detailed renovation budget. Sellers often hear that as “I want you to fund my preferred finishes.” Completed comparables would be stronger, but if they are unavailable, keep the explanation simple: market time, current condition and financing...