IMO it gets easier once the right support is in place.
With that in mind, when you say DD is EHE and you are trying to get her into SS, where are you in the process? Does she have an EHCP? If not, have you requested an EHCNA? If she already has an EHCP, have you appealed to SENDIST? If you are mid-appeal, have you requested an expedited hearing? In the meantime, you can inform the LA you are no longer EHE and they must make arrangements to ensure DD receives a suitable full time education and anything detailed, specified and quantified in F. If they refuse, delay or ignore your request for AP, you can enforce this, including via judicial review if necessary.
Why is DS on a reduced timetable? Is alternative provision in place? Does he have an EHCP? If so, have you requested an early review. If he doesn’t have an EHCP, have you requested an EHCNA?
Have you requested transport?
Have you had social care assessments? A carer’s assessment for you and assessment by the children with disabilities team for DC?
Are DC in receipt of DLA and are you getting all the right UC elements? Have you applied for any grants you are eligible for?