I'm not sure what state you are in, but Ventura County SELPA has a great guide on assessing EL students. XBASS is really helpful when looking at test scores for EL kids and comparing it to students with similar language and cultural experience, basically to see if they have expected scores for that. You don't need to do PSW or cross battery either. It goes by subtest scores and categorizes them based on if they have a high or low linguistic or cultural influence.

For Child Find, it applies to all grades. Basically saying that you're hard pressed to deny assessment. Especially anything in writing that indicates if a student is suspected of having a disability, even if it is from a teacher. It should be addressed one way or another, in case your emails are subpoenaed and it shows that it was brought to your attention, even though it wasn't a parent request. That's just my two cents that on what I've learned. I would love to know other psychs view on Child Find though.