Would the three other roommates (not renewing) have to give consent (in form of writing) for the Landlord to use the original security deposit for this "transfer lease"? 

What you do from here is find out who did the job, when, and if your state law covers a certain period AND if the previous owner's contract with this plumber covers warranty AND if it was transferable (as the warranty is not issued to you).

The role of the local project manager would be to check out local deals prior to purchase, locate and coordinate subtrades, check up on the contractors, and look in on the property regularly and when needed. 

Sales and transfers of title do not trigger reassessment.

Considering your 25, unless you're receiving an extremely large gift from your parents as a down payment your home probably won't be expensive enough for the commission to be worth it. 3% of a $300k is only $9, and by the time to figure in a transaction coordinator and your broker split you'll be walking away with half that.

They transferred me over to Cal Vet.

Then I can periodically transfer money to the original bank?

It's an old school way however that is fraught with difficulties - determination of equity and value, transfer of deed, and of course the opportunity to place yourself at the mercy of the person across the table.The post Starker method of sell (documented by QI with funds held by QI) followed by purchase (documented by QI with funds transferred in by QI) is ever so much easier.  

The deed was transferred over to the new owner and they claim to have made payments to the bank.

Ask tenants to submit repair requests online and PM or yourself check the requests on daily basis and the prioritize and coordinate the repairs.4.