Are These Legitimate Property Management Policies?

[Ima Renter]

Hello!
I recently found a house being leased that I applied and got approved for. The house is managed by a property management company representing the landlord.

The house is already in move-in condition. A previous applicant was approved but backed out because of financial problems, I was told. It was verbally agreed upon that my intended move-in date of mid-February (about a month from now) is fine with the land-lord. The property management requires that I put a holding deposit of a sizeable amount so that the house can be taken off the market listings. This deposit is non-refundable if I decide to back out and not rent the house anymore. In addition, the property management requires that:

1. the deposit be made in money-order or cashier's check (ie, no personal checks accepted)

2. the rental agreement be executed near the official move-in date (ie, about 2-3 days prior)

Are the two requirements above legitimate? I'm concerned that after I put in my non-refundable deposit, I'll be "pressured" to accept the actual terms of the rental agreement when it's finally drafted. Because if we do not agree on something in the agreement and I refuse to sign it, they might say that I'm backing out and hence have to forfeit my deposit. How can I protect myself against this possibility? I'm willing to sign the actual rental agreement and put down the full deposit and first month rent anytime.

Thank you in advance for any inputs, and best wishes.

Ima Renter