Thank you for the clarification that it's per Kb. Unless I'm blind, I don't see that specifically made clear on the withdrawal page.
It's mentioned in the FAQ/on the blog.
Would be worth making it clearer
Probably left out there for the ease of it (not to overload the window), but could be a good addition.
and if at all possible, give an 'estimate' of that actual fee paid
As said, an estimate of transaction sizes is hard to make, due to the nature of the system.
The important variable for transaction speed is not the total fee paid, it's the fee per size ratio, so what you need to know for estimating your transaction speed is your per kB fee, not your total fee.
I don't think estimating the size and total fee would provide any additional value to the user (it doesn't change the amount you'll have to pay or the speed of your transaction).
Read about our Bitcoin Gold (BTG) contingency plan on our blog. Those interested in tracking the progress, there's a countdown here:
https://www.crypto-news.net/bitcoin-gold-btg-hard-fork-countdown-clock/So far, it looks like the block is going to be mined late on the 24th, not on the 25th.