Skill/Power equivalency for Divine or Arcane Magic Research powers

As a way of understanding the Custom Class rules, I have been reverse engineering a few of the Core classes before I build some out for my campaign.
One thing I could not suss out was the equivalence for Magic Research/Create Items/Cast Ritual Spells powers should one want to trade those out. It is of interest to me since that is not a subsystem I plan on using in my campaign and I would like to slightly retool the Cleric class by pulling those powers out.
My initial thought was that it equated to 2 initial skills traded for 3 at higher levels, but I am not sure if that fits the progression schemes for tradeoffs…

Ok, maybe my previous question was not clearly stated enough to evoke a reply…
First off, all my run-throughs with the custom class rules have worked very well. I have been able to build both new classes and reverse engineer existing classes so the rules feel pretty solid.
I have only encountered one scenario that could either benefit from some clarification in the rules or that I have simply failed to understand.
The following would apply to Arcane as well as Divine, but I am working the cleric class at the moment.
When selecting a value for Divine the class gets the abilities to turn undead, cast spells, and engage in magical research. Further on in the rules it is noted that the core powers for Clerics encompass divine spellcasting and turning undead and that they cannot be traded out for other powers.
That seems pretty straightforward, but it is the magical research and item creation powers at 5th, 9th and 11th level that have tripped me up a bit.
Question 1: Are any or all of those powers considered to be core powers of the class? If the answer is yes, then it might help to note that they can’t be traded out in the Custom Powers section.
Question 2: If the answer is no, what is the proper initial power level for the 3 powers? Are they treated as 3 individual powers or did they start as 2 powers that got traded for 3 or something else entirely? Again a note or example would help clarify that.
Question 3: If the 3 powers were to be removed from the class, what would be the appropriate XP curve modification?

They are considered core powers of the class and can’t be traded away.
If, for some reason, your campaign needs to allow classes to purchase magic research as powers, you could use the Dwarven Machinist’s class power for reference.
I would generally not allow them to be removed from a class to get other powers.

Thanks, I am really looking to remove the powers completely from the cleric and the game for that matter, hence my trying to figure out their cost. Easy enough to simply remove them since the base cost for a cleric is not out of line with the other classes.

Out of curiosity, why are you removing the powers?

I am removing them because the setting is low magic and while there are magic items to be found, the research and item creation rules really don’t fit. In fact, there are no magic users as PCs or NPCs in the setting either and no one has really missed having access to the class. It was a bit of an eye opener, it sure changed how the players perceive the value of the cleric class.