Good to know about the rear seat access, most cars I've seen or had to work on required a tank drop to access the filter and pump so not having to go through that would make my day. 

I have not had a load test, no. The car came with a brand new 775 CCA battery in good health but I'll definitely look into a load test, just to cover all my bases.

Edit: 
Checked clamps and everything, found one slightly loose before leaving work. However, this morning, still back to my starting issues so I'm going to eye my filter and pump as the culprits

You should be able to access the in-tank fuel pumps from inside the car - just remove the rear seat bottoms and there will be a couple of access ports. The filters in the tanks do get dirty, so it would be worth a look.

Also, have you had the battery load tested - just to be sure. Not just the voltage but a load test.

Fuel should be free of water, I was on 1/3 of a tank when I changed the pump and I immediately drove to get gas following that repair.

I'll double-check my clamps and lines though. The hard line gave me grief the whole way so that's the main one I'm going to double check. Clamps I can check before I head home from work today. 

I'm hoping not to have to drop the tank for that other pump and the filter but it will be what it will be.

Welcome!
I don't know anything about your car but I would suspect a clogged fuel filter or an air leak between the tank and the pump. Re-tighten any clamps you may have touched and inspect the rest of the fuel line. Is the fuel fresh and free of water?

• I bought my 07 Mini Cooper S about a year and a few months ago and over the last few months I've had starting problems. When I first start my car, it will almost turn over and then stall. I have to repeat this process several times before the car will finally turn over. Once started, I have no problems getting it started but it shakes and hesitates to get up and go.

I've changed all spark plugs and ignition coils, replaced the HPFP yesterday, since I had read this was a common issue in this model and yesterday, the car started right up, had all her power and was a joy to drive again. Today, I went out to start her and I'm back to starting issues.

The previous owner of my car did not take care of her as they should have so I'm curious if this is a side-effect of them gunking up the engine with infrequent oil changes or if it can be solved by changing the other fuel pump and fuel filter.