Car not starting

[SeattleBimmer]

Hello,

This is my first post so bear with me. I am including as much information as I can even if it may seem irrelevant. This way if I made a wrong assumption, you guys can point that out. I've read everything on this issue and could use some other ideas.

The car:
2006 X5 4.4 N62 engine, 108K miles

Experience: I'm fairly inexperienced but am very competent if there are detailed DYI videos or forums. TO give you an idea, I recently completed changing out the valve stem seals using the AGA tools.

Issue: Car will not start. It does not crank. It drove fine the days before. No dash board battery light or check engine. Never had any indicators like long cranks before starting. The only issue I had was a slight leak from the coolant hose connection into the firewall. I removed this hose to remove the valve covers. The leak was due to not fully tightening the hose clamps. The leak does not drip onto any electrical components that i'm aware of. I noticed the smoke from the coolant leaking on to the hot engine for a few days (didn't have time to fix so I kept adding coolant). I finally park the car in my garage and proceed to remove the cowl that houses the cabin air filter, along with the air vents to be able to get to the hose clamps. Tighten the hose clamps, topped off the coolant. Go to start the car and no sound but a single click.

Diagnosed:
1) Assumed the battery was weak so I jumped the car and it started so I thought I was right about the battery.
2) Removed the battery and brought it to Napa to get it checked and they said it was fine.
3) I decided to charge to the battery overnight. Tried to start next day and still no crank.
4) Thought maybe the battery was fine but nearing the end so decided to get a new battery. As far as I can tell, the old battery was not an AGM battery so I got a standard battery which also meant I did not need to register the battery.
5) Next I checked the starter. Removed the starter and brought to Napa, they tested it twice. I personally tested the starter at home as well (just curious cause i've never done it). Solenoid worked fine, motor worked fine, cleaned up the starter connections, re-installed starter, still no crank
6) checked all my fuses in the DME box (passenger engine bay near window) except the Integrated Supply Module (more on this later). Checked fuses in the glove box, checked fuses in the rear trunk. The only blown fuse I found was for the cigarette lighter.
7) decided to check relays next, could not find a relay for the starter. I've read other forums that this model may not have a starter relay. Either way it was very hard to get a definitive answer to if this relay exists and where its located so I just checked a few of the relays I thought could be the starter relay in the DME box.
8) Read that the EWS could be the problem. I decided to order a new key from BMW ($250) thought i would need a second key anyways so killing 2 birds with 1 stone. I tried the second key, same result, no crank.
9) Tested the ignition switch voltage to the starter. With the key turned to the ignition position, there was voltage going to the starter lead. The voltage across read 11.5. I checked the battery right after and it was 12.5 so I'm not sure what that means. This could be why even with a new battery the car won't start because the volt at the ignition switch is less than a full battery. I'm thinking of changing out the ignition switch for peace of mind but I don't have any other symptoms of a failing ignition switch so i'm a bit skeptical that this will resolve the issue.

My next steps will be to change out Ignition switch and then the Integrated Supply Module. I've read that this could be the issue. And if this doesn't solve the problem then i'm stumped. If its a failing EWS then that way above my level so i'm bringing it to the dealer.

The other thing I haven't looked at is the alternator. I'm not really sure how this could be the problem since my problem is not a draining battery but I did recently partially remove the alternator to get to the upper timing case gasket so I'm worried maybe I did something. Additionally when I removed the coolant hoses, there was some spillage that could have damaged the alternator. Does this sound feasible?

And yes I have checked the battery connections, they are very clean and secured.

Any ideas?