What types of things would typically be discussed at a transition planning meeting for an HFA special education student?

Transition planning is part of the IEP meeting commencing with the annual meeting in which the student turns 14. Transition planning is long range educational planning for the student's future. The determination of the need for an aide for next school year is part of the IEP Team's determination of the child's special education and related services needs. Likewise the IEP Team determines if there is a need for parent training or home services. Your questions are fact specific to your individual child's needs and as such need to be discussed in the context of a consultation with an attorney knowledgeable in special education law who represents parents.

If you want them to hire outside workers like this, you will usually have an uphill battle. Cost is a factor (though legally not the driving factor) in decisions for appropriate support. And these days schools often draw lines in the sand and make you take them to court. Get a lawyer early in the process and be proactive here. This is your only chance to do this before having to take them to court. They have done it from the other side (yes, sadly, that's how it is) thousands of times. You need someone with experience to help argue this for you and bring in experts.