I'd say have $5-10K for out of pocket business expenses after "getting to Chile" expenses. The things that you need to begin the program - plane flights, visa costs, mandatory 6 months of travel health insurance - can easily eat up $5K all by themselves, depending on where you're coming from. The visa fee for UK citizens is almost $1500, for example.
If you don't have enough money to pour in up front, cash flow will drive you crazy. Put together a six-month budget, even if it's loose. Put every expense you can think of in it. Reimbursements can only happen once a month and you absolutely need to plan things out to get the most out of the funding.
Yes, they make it pretty clear that you should have $5k per person to get you on your feet. I took it pretty lightly but it ended up being quite accurate and we ran into some cashflow issues.
As for time on program overhead, minimum probably 2 days a month. Much more if you want to be more involved with the community. You are not forced to do much more than the reimbursement process and finding some ways to give back to the Chile. You could go to meetups and such 3-4 days a week if you wanted, a lot going on.
Great point. I initially thought I would float everything on my credit card until I got reimbursed. I found out it doesn't work like that unfortunately. You have to show that the credit card has been paid off for the transactions you are submitting.