The architect of a proposal to overhaul oversight of the government-sponsored enterprises is scrambling to alter his plan for an affordable-housing fund after the scheme came under attack by numerous lawmakers on Capitol Hill. H.R. 1461, the “Federal Housing Finance Reform Act of 2005,” passed the House Financial Services Committee last month by a healthy 65 to 5 margin. But a number of Republican lawmakers have criticized the bill in part because of one provision…