Would be much easier to do in plaster, even if textured.
The images below, are of an old window opening, overlapped by a new double door install. As forgiving as that dark paint was (2007), if they painted that room white today (2016), it would still look like that door had always been there - 140 year old house. The last picture before the close-up, is all the further out that I blended, didn't need to go clear out to corners/ceiling.
Remove ALL loose plaster first, then add in this order;
Wood Lathe > Stapled Wire Lathe > Structo-Lite > Blue Tape > DuraBond > Light Weight Setting 90 > Thinned Light Weight All Purpose Bucket (Do all texturing here) > Prime > Paint > Done
Outside of a detailed explanation of the work flow - if you follow the instructions on each product, as it appears on the packaging, they will all work, exactly the way that they are supposed to.