1) 2 years is a great lease period, 3 years is better.
2) You'd want to budget at least $1,000 per year as a lease fee, plus a good reimbursement maximum amount for travel/transportation/installation (or provide in-kind services for installation). If you can afford $2,000+ per year, great.
3) When we've done it we've made sure the artist remains the owner of the physical artwork, but we've provided insurance for it while it is on our premises.
4) We have provided LIGHT maintenance such as cleaning off mud and graffiti, but not addressed major deterioration--contractually that is the artist's responsibility.
5) We have found success by not giving all the funds to the artist up front--to get the 2nd payment, the work has to be removed on schedule. Otherwise the work could get abandoned.
(she/her/hers)