HellDiverUK

Ah yes, I meant to mention BlueIris.
I run it at my mother-in-law's house on an old Dell T20 that I upgraded from it's G3220 to a E3-1275v3.  It's running a basic install of Windows 10 Pro. I'm using QuickSync to decode the video coming from my 3 HikVision cameras.  Before I used QS, it was sitting at about 60% CPU use.  With QS I'm seeing 16% CPU at the moment, and also a 10% saving on power consumption.
I have 3 HikVision cameras, two are 4MP and one is 5MP, and are all running at their maximum resolution.  I record 24/7 on to an 8TB WD Purple drive, with events turned on.  QuickSync also seems to be used for transcoding video that's accessed by the BlueIris app (can highly recommend the app, it's basically the only way we access the system apart from some admin on the server's console). 
Considering Quicksync has improved greatly in recent CPUs (basically Skylake or newer), you should have no problems with an i7-8700K.  I get great performance from a creaky old Haswell.

Ah yes, I meant to mention BlueIris.
I run it at my mother-in-law's house on an old Dell T20 that I upgraded from it's G3220 to a E3-1275v3.  It's running a basic install of Windows 10 Pro. I'm using QuickSync to decode the video coming from my 3 HikVision cameras.  Before I used QS, it was sitting at about 60% CPU use.  With QS I'm seeing 16% CPU at the moment, and also a 10% saving on power consumption.
I have 3 HikVision cameras, two are 4MP and one is 5MP, and are all running at their maximum resolution.  I record 24/7 on to an 8TB WD Purple drive, with events turned on.  QuickSync also seems to be used for transcoding video that's accessed by the BlueIris app (can highly recommend the app, it's basically the only way we access the system apart from some admin on the server's console). 
Considering Quicksync has improved greatly in recent CPUs (basically Skylake or newer), you should have no problems with an i7-8700K.  I get great performance from a creaky old Haswell.

Just for completeness for anyone coming across this thread, the Supermicro SAS2LP-MV8 works fine in Windows 10, passes SMART and allows spin down.  It's a good card, I have had great success with mine.

If you're using a laptop "outside", then you could set up OpenVPN on your server (or if you have a decent router, on that).  Connect to the VPN and you can work as if you're at home.
 
I do this from work - I have OpenVPN running on my Asus router, and connect in.  I can access everything across the VPN.  As the VPN data is compressed, it's pretty quick.

Not a problem. It's a bit more complicated, especially as it basically requires the use of the File Placement rules:
Install the SSD OPtimizer, enable it, and configure it. Set File Placement rules for the documents, pictures, etc, selecting every disk except for the SSD drive(s).  On the Settings (main) page for the balancing, uncheck the "File placement rules respect real-time file placement limits set by the balancing plug-ins".  This tells the software to respect the file placement rules, even when they violate the real time placement limits set by the SSD Optimizer. 
 
 
If you want the File Placement Rules to keep the files on the SSD drive, regardless:
Install the SSD OPtimizer, enable it, and configure it. Set File Placement rules for the folders/files in question etc, selecting the SSD drive(s) (and any others).  On the Settings (main) page for the balancing, uncheck the "Unless the drive is being emptied".  Normally, the SSD Optimizer balancer attempts to "empty" the SSD/cache drives, clearing them out. Normally, the balancers will respect the file placement rules *except* when the drives are being emptied. Meaning it will not respect the file placement rules properly.  Unchecking this means that the file placement rule will *always* be respected, even if a balancer (including the StableBit Scanner balancer) wants to empty out the drive.      These rules are not mutually exclusive, meaning that if you want to do both, just set the rules and settings accordingly, and you can get both options.