Niko, the #4 option seems best...only one wiring job to do and less chance of bug with one sustem. Which do you recommend? Your opinion is greatly appreciated. Thanks in advance for your time.
The #4 is most difficult, because there are no 2ch 1080p with parking mode that would be up to latest high standards of video quality and stealth design at same time.
Best video quality is on Panorama X2 ( both channels 1080p 30Fps with 15Mbps bit-rate ), but it has a fussy firmware which need a special attention and know how how to manage it. Firmware to fix bugs is still under development. There is also a Blackvue 750, but I dont have personal experience with it and can relay only on feedback from others ( which is obvious if you read thread ).
The last option for you might be a Thinkware F750. I have experience with earlier model and must say it is one of best built dashcams brands, high-end feeling and quite stable performance, the only downside with this model is that each channel records only 10Mbps which is not the best bit-rate for Ambarella A7 processor. Not sure if Thinkware has plans to rise bit-rate, because total combined safe bit-rate for stable long term performance of dashcam is 20Mbps on A7 chipset.
As it is your first dashcam, I would suggest to start with something simple, cheap but at the same time reliable. You may take a look at Blacksys CF-100.
https://dashcamtalk.com/forum/forums/blacksys-cammsys.86/
It is also Korean high-quality built dashcams system ( 1080p + 720p ) with quite good video for it's specs ( sale price is around 100 usd / normal price was around 200usd ), has parking mode ( need optional battery discharge prevention device, around 30 usd ).
Or you may also have a look at Street Guardian SGZC12RC. It's a 1 channel remote lens with pre-buffer recording which is useful for parking motion detection, capacitors. You need to buy two of those plus BDP device. Of course it will be over your budget, but still worth to read other available options.
https://dashcamtalk.com/forum/forums/sgzc12rc.162/