LOS ANGELES—Gov. Gavin Newsom and legislative leaders will announce a multibillion-dollar deal March 1 aimed at enticing schools to resume in-person instruction for young students by April 1, but union demands for COVID vaccinations of teachers and reduced transmission rates make it unlikely L.A. Unified will meet that date. According to reports out of Sacramento, the deal—which still needs formal legislative approval—would create a $2 billion incentive pool, with money doled out to schools that reopen campuses for students in kindergarten through second grade, as well as high-need students of all ages. Schools that fail to open by April 1 will lose 1 percent of their portion of the funds for every day they miss the deadline. The money would be available to schools in counties that have an average daily new COVID case rate of less than 25 per 100,000 residents. Los Angeles County and other Southern California counties …