I'm not well versed in plaster and hopefully one of our plaster guys will chime in later.
The hard coat is the plaster base coat. With the depth of the holes, I'd be leary of using the ready mix joint compound. Durabond is a good substitue for plaster - especially for those of use with no actual plaster experience. You need to make sure the area to patch is clean. If it is still dusty after cleaning/dusting it with an old brush, I like to prime it so the 'patch' has a better bond to the wall. I've heard the plaster guys recomend a product called 'plaster bond' [?] that might be better than just plain old primer.
Remember durabond is a bear to sand so the neater you apply it - the easier your job is
You can find durabond in the drywall section of most any big box store. It comes in a bag [powder - add water and mix] If they have more than 1 to choose from, the #s represent the working time. I like the 20 minute mud because of the fast turn around but you would be better off with the 90 minute mud - it dries slower = more time to work with it. Only mix up what you have time to use and throw away any left over mixed mud. Don't try to complete the job in 1 session. Do most of your filling the 1st time and then when dry, mix a smaller amount that you can use to dress/level it up.
BTW - no need to use the quote button. use either the post reply button or the icon on the far bottom right - to the right of quote. makes for a neater easier to read thread
