Replacement EGR Cooler hoses got delivered mid last week.
New hoses snap tight and do not feel loose or rotate freely as reported by @deptrai in post #254. Vacuum test passed as well.

I put everything back together, filled coolant with vacuum filler.
I had to top off less than 100ml coolant after final venting procedure.

I ran engine for several minutes - it took some time to warm up.
Unlike before thermostat replacement, temp easily passed previous 77C mark and continued to rise. The max coolant temp was 97C, at which point fan kicked in and cooled engine down to 89C. (This was my first time I've seen X5 fan in operation since I bought the car new)

I realized that I have 2 hands only, but to put flange bolts need at least 3
- one to hold mirror
- another to hold flash light
- and another to drive the extension with bolts.
You can hang your mirror and flashlight as shown on the picture below:


Once again, huge thanks to entire community.

Below are other resources that could be used as complimentary references to this DIY

newTIS REP instructions
17 11 035 Fan assembly removal
17 00 005 Coolant Drain
11 71 100 EGR Cooler Removal
11 53 000 Main Thermostat Replacement
17 11 040 Transmission Thermostat Replacement
17 00 039 Coolant Fill and Vent

Youtube