Philip - I'll do my best to answer your multiple Qs but the mix of registered and unregistered and dealing with your deceased Mother's property would always prompt me to recommend that you seek legal advice also
1. The applicant is the name of the person you are applying to register as the owner. That would not be your sadly deceased Mother. As she has passed away you will need to apply to register the land/property as appropriate and I assume n your name as her beneficiary. Our
online guidance will assist you re what is required
2. If the value of the land is less than £6K then ID evidence is not generally required
3. If you are applying for merger then panel 4 of the form AP1 would be the place to request that. ID verification is not needed for a request to merge.
4. I assume the freehold is already registered in her name so the value you refer to appears not to be relevant. What is relevant is how the legal ownership of both the freehold and leasehold titles is to be dealt with and by whom. Again, if you are the beneficiary I would suggest you need to consider making an application to transfer the legal ownership to yourself and requesting merger as part of the same application as appropriate
5. GOV.UK provides
guidance on how to certify a document. Each page does not need to be certified and we may accept certification by the person submitting the application
6. As it seems very likely you will be transferring the freehold and leasehold into your name and merging before the purchaser will complete there would be no additional fee for the merger. You would be paying a registration fee for the Transfer of ownership
In no way to be challenging but simply to flag the need to consider matters further, on the face of it you have a broad understanding of what is required but your start point of trying to register your late Mother as the claimed land is incorrect.
Your buyer will not complete I suspect until the registrations are resolved and the mix of leasehold, freehold and claimed land straightened out. To that end I would again recommend seeking legal advice primarily with regards the claimed land but also with regards registering the ownership in your name as the beneficiary.
In a normal sale of a freehold/leasehold house the buyer would invariably be able to rely upon the registered titles plus probate. However the additional land and the need to register a claim complicates matters and I suspect you will need to register everything in your name as the beneficiary before a buyer will complete. That is though where your legal advice must come in
I hope that helps