Congress may be the next route for home-equity lenders after losing their court fight to nullify federal thrift regulations on prepayment penalties and late loan fees under the Alternative Mortgage Transactions Parity Act. But industry observers say even a legislative option is uncertain, as the National Home Equity Mortgage Association ponders other alternatives or strategies to get the Office of Thrift Supervision to reinstate parity act preemption of state laws regulating prepayment and late