As a landlord who lives abroad my advice is
1. All monies to your account, it should be an account that is specifically for rent. You will have to decide how your agent handles the deposit and costs for repairs, how you will pay them. And most importantly who registers with the PRTB.
2. You can do your tax returns under your own PPS number. Your accountant should be helpful in this regard, and you are on the right track hiring an accountant.
3. Can't reminder the liability date for NPPR offhand, but that is the key date the liability date. Don't forget there is the new property tax as well.
Strickly speaking from a revenue point of view the tenant's should deduct tax from the rent, but it's not a point revenue enforce, particularly with tax complaint landlords.