As I understand it you are considering buying this old house. You are looking for someone to help with the repair cost.
Do you mean that you are looking to get estimates for all the repair work or are you looking to turn this property into "low income housing" and would like to see if this property can qualify for Community Development Grant money?
If you are looking for estimates:
I would hire a Home Inspector. But, only if the inspector has to be licensed with the state and demonstrate a general knowledge in order to get licensed and is insured and bonded.
Note* Home Inspectors are poping up all over the place these days. In some states all you need to do is print up some business cards and "poof" your open for business.
A good Home Inspector should be able to give you a rough estimate of what it would cost to repair or replace what is there. If you are getting a mortgage on this property, I would think they would require an inspection.
After you receive a copy of the inspection report, get two but, not more than three estimates. Too many estimates will just become confusing. Depending on the work that has been quoted, I would add about on third more for the hidden problems.
Start with the foundation, outer shell and roof, then the inside work. If there is alot of rehab work to be done here, you may want to look for General Contractors to give you estimates on the whole job.
If you are looking to buy this as an income property:
you should contact your local Community Devlopment office, (call your Town or City Hall), They will generaly inspect the property and get the estimates for you and provide grant money to do the work. In return you will have to sign an agreement to provide Low Income Housing for a set period of time.