Re Architects, you can search the RIAI website by region to find architects in your area (www.riai.ie). I wouldn't advise you to limit yourself too much by location - if you have a friend who had a good experience with an architect in Sligo/Wicklow/wherever, tlak to them. Your eventual builder should ideally be localish, but I would not prioritise proximity to your site as the main selection criteria for an architect, engineer, etc.
Re. Local Authority Fees, phone up the council and ask them. The days of them being able to pick a number out of a hat are gone, and they should be able to give you an accurate estimate of what your fees will be, depending on location, waste and mains water situation, etc.
To double check, look on the Meath County Council website for recently granted permissions for similar type developments in your area, the charges will be listed on the Grant of Permission document.
On the MCC website there is a ready reckoner, if you put in the size the house you wish to build it will tell you how much you will be liable for. This figure also depends whether there is public mains water and sewage.