Hi,
I can imagine how exhausted you must be after 3 attempts.
Let me try to answer your questions to the best of my ability.
1) a) if I should only give one section to be re-evaluated i.e. Writing (where I badly need 0.5 increment) or
b) add Speaking section too (Speaking went well and was expecting atleast 8 this time + if score gets changed money will get refunded).
Be realistic here, if you decide to re-evaluate your writing think if you answered all parts of the writing tasks, did you correct your grammar and spelling errors? Did you organise your ideas logically and so on.
If you feel you have done all of that and you deserve a higher score, sure you should apply for remarking.
You can apply for W and S to be reevaluated since that increases your chances of money being refunded.
c) Another option is to give W + R together. If 0.5 increases in both, CRS score would be 430
Reading and Listening scores almost NEVER change.
2) Are the chances more to get the reevaluation result early if given only 1 section for rechecking instead of 2
There's no such guarantee.
3) When sending the docs for EOR, do we need to send the original hardcopy result that we receive via courier or the result in pdf format from idp site would work ?
Yes you need to send the original hardcopy. Also you cannot use the result while you have sent it for remarking.
I am really looking forward for a sincere advice as I have already given 3 attempts and have no energy left to go through that grilling process again for the 4th time.
Again like I mentioned, I understand how you feel but don't give up. I've seen people attempting 8 or 9 times before they got the scores they needed! Good luck!
I hope this helps!