I would not take any courses on line in conjunction with an LPN course, because it would be very distracting. Most LPN schools are full time, 5 days a week and there are many assignments, clinicals, and practice labs that have to be done for the entire length of the program.
It is also very true that you have to ensure that your childcare situation is air tight before you enter ANY nursing program because they have a limit of latenesses and absences. Many will say that if you are absent twice, or late three times (ESPECIALLY to clinicals), you may be expelled from their program. And, the LPN programs are jam packed with information within a short span of time, so, missing any time will be determental to your grades. As much as I, personally, understand that as a parent, our children come first, but, most schools are not that empathetic towards childcare or jobs. They feel that this behavior would continue as a nurse that is not dependable (not MY words, but it may be THEIRS).
Good luck in CNA school and more!