Nothing unusual. HK are losing ground rapidly.
Any DSM2/DSMX compatible you want.
12.8V - 3.2v per cell id the best setting. You could do 12.0V - 3.0v per cell as an absolute limit. Any lower and you risk shortening the pack's longevity.
If you're referring to a quad/multicopter frame than no, there is no frame that large available at this time.
Your TX has the EU version firmware and is only able to bind DSMX receivers. The R610V2 is only a DSM2 protocol and is incompatible with your transmitter.
You need to ensure you only purchase DSMX compatible receivers.
No. None in the range that will withstand 5S
Google "ESC unidirectional 40A" which might help you in the right direction...
No. It requires an ESC.
Check the 'files' section on the product page.
Very few HK models have printed manuals - keeps costs down.