Planning a water-cooled 5900x + 3080 Ghost S1 Build. Need Pump recommendation or suggestions.

[theOldHunter]

A long time ago (6 years), I build a Ncase M1 SFF PC: NCase M1 Build
While I have built other PCs in between for friends, I am again on the path of building a new SFF beast for my main personal rig.
I have decided to go for a full custom loop in the Ghost S1 I had kickstarted few years ago but never got to build.
Done my research and have already bought most of the components. Well, except the pump. (And other watercooling related parts)

I would like some opinions on my plans based on the component list.
Also, any tips/suggestions/improvements are much appreciated and welcome. Especially, if based on your personal experience on building a water cooled machine.
Since it is my first watercooling build, everything is new knowledge for me.

The plan is for a single custom loop which includes the CPU + GPU using a single 240mm radiator with a separate Pump that can fit in the case.
Then undervolting both CPU & GPU.

Inspirations:
OptimumTech - The Liquid Cooled Ghost S1 is Complete! - YouTube
GGF Events - SUPER CLEAN! Dual Loop Ghost S1 SFF Build - 5900X | RTX 3090 | 64GB - YouTube
And many helpful posters on reddit and other forums.


Component list (Purchased):
Case: Louqe - Ghost S1 Mk.II
CPU: AMD Ryzen 9 (5900x)
Motherboard: ASUS - ROG Strix Gaming (X570-I) Gaming Mini ITX AM4 Motherboard
Memory: G.Skill - Trident Z Neo 64GB(2x32gb) (3800MHz) (White/Black/RGB)
GPU: Zotac GeForce RTX 3080 10 GB GAMING Trinity OC
Storage: Samsung 980 Pro 2 TB M.2-2280 NVME Solid State Drive
PSU: Corsair SF750
Case Fan: ThermalTake ToughFan 12 x2

Water Cooling (Purchased):
CPU Block: EKWB - EK-Quantum Velocity D-RGB - AMD Nickel + Plexi
GPU Block: EKWB - EK-Quantum Vector Trinity RTX 3080/3090 D-RGB - Nickel + Plexi
GPU Backplate: EKWB - EK-Quantum Vector Trinity RTX 3080/3090 - Black
Radiator: Alphacool - NexXxoS ST30 Full Copper
Tubing: Soft Tubing 10/16mm
Fittings: EK- Quantum Torque STC-10/16 - Black x10
Angled Adapters: EK-Quantum Torque Rotary 90° - Black x2
Coolant: EKWB or ThermalTake Semi-Transparent

Not yet Purchased:
Fittings: Koolance LXG-2 (Need the low profile. Not available for me yet. Searching...)
Pump: ???
Reservoir: No Space. So mostly a pump top with small space.
Alphacool Leak Testing Tool incl. Pump
Alphacool Eiszapfen temperature sensor G1/4 IG/IG mit AG Adapter - deep black
Alphacool Eiszapfen quick release connector kit G1/4 inner thread - Deep Black

Part list also posted here:
Ghost S1 Build » PCPartPicker
Ghost S1 Build » builds.gg


Questions:

1. The pump especially is a difficult decision. (The space + the design.) I like the Alphacool Eisdecke Dual Acrylic top which can take either 2 DDC or 2 DC-LT 2 pumps. But I don't know yet if it will fit in the case. I'm hoping Yes but I have yet to check. Either way (Dual or single), based on the fact that I have RTX 3080 + Ryzen 5900x, Should I go for DDC or DC-LT 2 pump(s)?
2. I have been unable to get the Koolance LXG-2 low profile fittings that most of us are using but I'll keep trying.
3. Thinking of including a Quick disconnect in the loop. Useful for future use?
4. I have read the drain port is very important. Ideas on how to better to position it in the Ghost S1?
5. About the fill port, is there a way to fill it from the top of the radiator. If I end up getting the Eisdecke, it will most probably be positioned at the bottom of the case.
6. Since it's such a tiny case, not planning for a dedicated reservoir but can buy one just to fill externally. But would like to avoid since I have already spent a lot on the components.
7. Any other accessories, fittings, adapters that can ease the building process.

Thank you in advance for your time.
Have a good day/night.