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If your dies have carbide sizing rings, lubrication is not required, though some like to use it anyway because of the greater ease with which it slips into the die.
Unless your chambers are unusually tight, you should find no issues with the 0.002" bigger bullet. The 44 WCF COL is about 0.020" shorter than the 44 Special, but the case is about 0.152" longer. So if you use bullets intended for the special, the crimp groove will cause the COL to be 0.172" over max. If your cylinder will tolerate that, no problem. But if it won't, you will probably want bullets whose crimp groove is intended for the 44 Magnum. They will still be long, but only by 0.042", which your cylinder is less likely to have a problem with. However, the greater seating depth will mean the actual powder space you have is less than in the 44 Special. The same applies to seating a bullet that has no crimp groove. If you seat it to WCF COL, you will have more brass gripping the bullet than you would in 44 Special, but will actually have about 5% less powder space.
Since the peak pressure rating of the WCF is only about 500 psi higher than the 44 Special, I would call that noise and just assume loads for the WCF at WCF COL will be about 2% lower than for the 44 Special with the same bullet. If your cylinder has the extra 0.172" so you can use 44 Special bullets at a COL of 1.762", then you will have more powder space and can increase the charge weight about 8% over 44 Special.
Yes, slugging the bore is a good idea. So is slugging your chamber throats. You pick revolver bullets to fit the chamber throats, and those throats need to be equal to or larger than your groove diameter; preferably a couple of thousandths larger, and reamers can be used to make them that way if they are not already.