Do I need to do anything to my starter?

I fed my starter last night (Day 3 - Pineapple Juice/WW) at 6:30, by 11:00 it was only millimeters above the line so I went to bed. At 7:00 this morning I found that it's expanded a huge amount! I had to loosen the lid a little to let some gas out so the jar wouldn't burst, I left the lid on keeping it just loose enough so that it won't explode. It's now 11:30am and it looks like it's starting to VERY slowly deflate. It smells like a strong yeasty beer, yum!

Is there anything I need to do to it before the next feeding at 6:30 tonight? Tonights feeding will be the first of UAP and water.

You didn't mention a feeding between 6:30 last night and the 6:30 feeding tonight. As long as it smells good, it should be fed when it begins to deflate. As far as I know, the pineapple juice solution fixes the leuconostoc problem, so this is not a false rise but the real thing. The yeast will start to go into hibernation if they're not fed soon.

Yes, I've only fed once per day for the last 3 days. Last night I noticed tiny bubbles forming and found this monster in the morning.

Should I feed it another round of pineapple juice and WW or should I move on to UAP and water?

Per the instructions at Debra's post:

Day 4: (and once daily until it starts to expand and smell yeasty), mix . . .
2 oz. of the starter (1/4 cup after stirring down-discard the rest)
1 oz. flour** (scant 1/4 cup)
1 oz. water (2 tablespoons)

Once you have yeast growing (but not before), you can and should gradually step up the feeding to two or three times a day, and/or give it bigger refreshments.

Nicely done - you're on your way!

I went ahead with the first UAP and water feeding 2 1/2 hours ago and it's already more than doubled and is deflating again... I guess this means I should feed it again?

Since it already has a STRONG yeasty beer smell when I'm feeding it at 2:1:1 ratio, is it ok to move to a 1:1:1 or 2:2:2 ratio?

If it is smelling yeasty and it is rising well, changing the ratio to 1:1:1 or even 1:2:2 would not be a bad idea. The stronger it is, the more you can feed it.

That said, if you like a more sour bread, there is such a thing as feeding too often.

Debra Wink says this (and a ton more) on the subject in this thread

It's the regular dilution through feeding that shrinks the bacterial population here, because they aren't keeping pace with the yeast, relatively speaking (and starter ripeness, and readiness for feeding is determined by yeast rise and fall)

I would DEFINITELY recommend reading it if you have a few minutes. It's very informative.

Going to a 1:1:1 ratio and feeding twice a day would be good for now?

The starter has had another rise since the second feeding and I'm not sure if feeding it a third time is a good idea. Should I wait until tomorrow to do another feeding?

In my experience at this stage, feeding twice a day for now will allow the organisms that produce the sour flavor to grow and flourish.

I feed it twice a day for about a week or perhaps longer, until the starter smells and tastes sour. To reduce the amount of flour I use, I keep only 20g of starter when I am refreshing, and I feed about 30-40g flour (I'm not terribly picky when I do mid-week feedings, I'm a bit more accurate when I am building for baking) and 20g water.

Not terribly long ago I read a thread here where one of the resident experts (I believe it was David) said that keeping a firm starter will result in a more sour bread. This has proven true for me, so if you want to build sour taste fast I would recommend reducing the hydration percentage of the starter.