Is it ethical/standard practice for a lawyer working on contigency basis to ask for money up front to cover investigation and serving costs?

Yes it is standard. Whether it is ethical depends on the details. Normally, a contigency fee agreement should be in writing. It must specify what is covered and what is not. Contigency fees do not cover legal costs such as filing fees and serving costs. Whether it covers investigation depends on the agreement. It is not unethical if the client agrees to pay for the investigation costs up front.