@Will Liang
Hi Will,
Sorry for your loss. No words can describe what you and your family are going through.
Your brother was kind, funny, and excited about many things, especially his family. We had a lot of communication back and forth since meeting at K&M. We often laughed that I was a terrible French speaker but my wife, having studied French, could hold a conversation with any old man in a cafe in the streets of Paris when we lived there. We both missed the cafes tucked away in all the small streets.
I can help identify 2 of those rifles because I helped him piece it together. (I have texts/communications with him to prove it)
The rifle in 5.png is an Impact Precision action, likely Stuteville barrel chambered in 6 GT, sitting in a Manners PRS-TCS stock, Triggertech trigger, double pull Ckyepod bipod, Area419 Maverick suppressor.
The rifle in 6.png is an Impact Precision action (could be a regular action or the Titan [titanium version]), 6.5 Creedmoor Bartlein carbon fiber Stuteville barrel, Triggertech trigger, Atlas bipod, Foundation Revelation stock (lightweight version). Our goal during discussion was to keep it under 16 lbs, which it barely did, if I remember correctly.
Feel free to PM me if any questions. I can look through my text messages and see if we discussed any other firearms you listed.