COS H1 to H4 and H4 extension for child

Dear Anil,
My H1B visa extension is approved recently until July 2024.However my dependents H4 extensions were not filed along with H1 ext as employer is not supporting. I am planning to file stand alone H4 extension soon.
Here are my questions
Q1: Do I need to file separate applications for my spouse ( who was on H4/H4 EAD and moved H1 recently) since it’s COS from H1 to H4/H4 EAD and my child who will continue on H4 as my dependent.
My spouse got H1B approval in 2020 December and moved to H1B but with the same employer and the same job. My Spouse did not went outside of country for H1 stamping as well.
Q2: If I need to file separate applications, do both I539 applications qualify for online submission. By the I want to file H4/H4 EAD together so that they would approve at the same time so that my spouse would continue working during this transition.

Thanks!

I539 can be filed online if its a single application.

If you want to file H4 for both spouse and child together, its better to file paper application as per current rules.

Thanks Anil for your response. I am planning to file online H4 ext for my child for now.
Will file paper application separately H4/H4 EAD separately for my spouse later.
However I can not combine both H4 ext for child and H1 to H4 COS for my spouse together in one application right ( though it’s a paper based app). Please let me know.

Regards…

You should be able to combine multiple H4 applications to avoid paying extra USCIS fee.