Congrats on your first property. I think the $100 deposit is much too low. I require one month's rent as a deposit, and I require $300-400/pet additionally, no dogs > 25 lbs and no aggressive breeds (there are few insurance companies that will insure a property at all if you have certain breeds present). Some landlords make the pet deposit non-refundable, but I make all deposits refundable. I think this balances my interests and keeps the pool of potential-tenants sufficiently high.
Speaking of deposits, be sure to inspect your property occasionally, and if there is damage the tenant should repair it or be billed at that time. Many tenants say they will repair the damage when they move out, but you should require it to be done or paid for in a more immediate time frame.
I don't require renters' insurance, but I let new tenants know that my insurance doesn't cover their property. There is also a check box on the application where they indicate if they will have renters' insurance or not. You/your manager should make maximum reasonable (an oxymoron, perhaps) disclosure to the tenant(s) BEFORE they sign the lease, and anything not disclosed on the lease should be on a separate list of disclosures and signed by the tenant.
Regarding your manager, I would not give her a debit card just because it is too easy to abuse. I also pay with a credit/debit card over the phone when my maintenance person goes to Home Depot or wherever for parts. You can handle the entire matter on the spot this way. If the vendor doesn't take over-the-phone payments, use a different vendor. As far as I know, your manager should also be licensed and should have access to standardized forms/agreements.
Speaking of which, how is it that the manager lives on-site but there are two vacancies? Managing one property is not difficult, and you can probably do it yourself. If done properly, rentals run themselves once you put the systems in place.
By the way, I'm not an attorney or any kind of certified. I'm just a private landlord who has learned many lessons the hard way.