Hey there, for property management I would definitely recommend Towne Housing Real Estate. They are who I use and they are great. I dont have personal experience with any others but have bought properties that were managed by other management companies and they were not in good shape. Too be fair though, it could have been due to the reluctance of the owner to do the necessary work. Towne Housing can be a little expensive on the work they do but they do good work and almost everything is in-house. You also can use outside contractors for work as well. They are full service too and I have had a good experience so far. They charge 10% of rent and then a $25/per unit start up fee. Leasing fees are 1 month of rent.
I have worked with Vinny Ciffa over at Metro Roberts of WNY as my agent in the past and he was great. He recently put me in contact with @Brandon Kmiotek on his team though and he has been great and is on Bigger Pockets and an investor himself.
I don't really have any recommendations for contractors or mortgage brokers but Lake Shore Savings bank will do investment property loans to out of state investors with 25% down or 75% LTV for a cash out refi which is what I'm currently doing. Their rate is 4.75% fixed on a 25 year loan
Just curious as to why you are looking at the Buffalo market? What attracted you to it? It seems like Buffalo goes under the radar on a lot of posts, etc. when it comes to good RE markets for investors