Pumking Clone Conversion

I'm planning on doing a Southern Tier Pumking clone. I found this wonderful recipe online that looks pretty promising, but I don't do all-grain, so I've been trying to calculate the conversion to extract. Here's what I have so far:

15 lbs 2-row Pale Malt = 11.25 lbs of Alexander's Pale Malt syrup

I checked out an article that said that you should multiply grain recipe value by 0.75 to come up with the extract equivalent.

For the Victory and the Crystal 80L I was just thinking of doing the same calculation and then buying them in their crushed form and doing a specialty grain bag steep. Will this work?

I'm still a bit confused with the hops. I read somewhere that when you convert from all-grain to extract you need to up the hops by 20%. Is this the case?

Any other help would be greatly appreciated!

I do not know why you would need to up the hops. In fact, if you mash at a lower temp, you might even want to lower them IMO. An excellent recipe though, and I like that it included vanilla, as I really tasted that in their last years batch. I will be borrowing some tid bits from this one.