A.: Has a cat got whiskers? Of course you need an attorney, whether you have a mortgage in place or are paying cash.
You are spending a substantial amount of money in a real transaction. Even if you pay cash, you will be signing a number of documents agreeing to terms that the condominium association imposes, etc. For the tiny amount of money that the attorney will cost, it is to your advantage to hire one, if for nothing else as an insurance policy. If something does go wrong, your recourse would be against the attorney, who undoubtedly has insurance.