Hi Doug - I am an owner in the city and have some initial thoughts to share on the expenses side.
Initially looking over I think you are a little light on a few items:
Water/sewer - if you as the landlord are responsible to pay for water (most likely you will be) log in to the Baltimore City public works website and look at the most recent bill - http://cityservices.baltimorecity.gov/water/
One of my duplexes operates around $65/mo for water and the other has crept up to $150/mo - identical buildings, side-by-side, just different tenants, so always a good idea to double check actuals.
Insurance - get a quote if you want to tweak a bit. You may be close there on a monthly basis, that looks close to what I pay on one of my duplexes. I believe mine are about $60/mo.
Capex - looks light to me but this can all depend on the current condition and how conservative you want to be.
Repairs/Maintenance - looks light to me - I like to have 5% - 10% of gross income in there depending on the deal.
Taxes - double check if you haven't already on the Baltimore City public works site to get the actual bill - plan to appeal if they are high, but run with the as-is number in your numbers for now.
Hope this helps!