RE: Advice from experienced craft beer drinkers, please?

Take breaks in between, they are all very distinct in taste. Also, get proper glasses if you can, they affect the taste ;)

Imperial DIPA would likely be double hopped IPA, you can also meet those labelled as DDH IPA. It will be like a hard-core IPA - it's hops what gives this beer the most distinct features, and if you hop twice, it gets even pronounced.

Milkshake IPA actually contains lactose, as lactic fermatation was likely used besides of the common yeast one. It will be creamy, could have hints of vanila and/or chocolate blended with the typical IPA flavours. I'd drik that one separetely to enjoy all the tastes. Also, look for the malts, I guess wheat, or even oats could be used to brew this one.

India Pale Ale is a common IPA, I am sure you've had a couple of those.

Red IPA is a usually a stron American Amber Ale, although it could be an IPA brewed with red hop varieties. It's usually heavily malted, check the malts too ;)

And, obviously, enjoy!

Cheers!