It is odd... this array was working well in Windows on the pre-flashed Perc h710p, I'm not saying you're wrong but it would be very coincidental for the cables to go between switching OSs. Plus the Preclean scripts had no issues erasing the disks nor writing zeros across all sectors.
When I tail the /var/log/syslog and attempt to add a disk to the array, there is some output with this block seeming to be the most relevant:
Apr 19 15:24:11 Tower kernel: sd 1:0:6:0: [sdh] tag#3435 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=0x08 cmd_age=0s
Apr 19 15:24:11 Tower kernel: sd 1:0:6:0: [sdh] tag#3435 Sense Key : 0x7 [current]
Apr 19 15:24:11 Tower kernel: sd 1:0:6:0: [sdh] tag#3435 ASC=0x20 ASCQ=0x2
Apr 19 15:24:11 Tower kernel: sd 1:0:6:0: [sdh] tag#3435 CDB: opcode=0x28 28 00 00 00 00 00 00 00 20 00
Apr 19 15:24:11 Tower kernel: blk_update_request: critical target error, dev sdh, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 0
Apr 19 15:24:11 Tower kernel: sd 1:0:6:0: [sdh] tag#5249 UNKNOWN(0x2003) Result: hostbyte=0x00 driverbyte=0x08 cmd_age=0s
Apr 19 15:24:11 Tower kernel: sd 1:0:6:0: [sdh] tag#5249 Sense Key : 0x7 [current]
Apr 19 15:24:11 Tower kernel: sd 1:0:6:0: [sdh] tag#5249 ASC=0x20 ASCQ=0x2
Apr 19 15:24:11 Tower kernel: sd 1:0:6:0: [sdh] tag#5249 CDB: opcode=0x28 28 00 00 00 00 00 00 00 08 00
Apr 19 15:24:11 Tower kernel: blk_update_request: critical target error, dev sdh, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Apr 19 15:24:11 Tower kernel: Buffer I/O error on dev sdh, logical block 0, async page read
Apr 19 15:24:11 Tower emhttpd: error: ckmbr, 2197: Input/output error (5): read: /dev/sdh
Apr 19 15:24:11 Tower emhttpd: ckmbr error: -1
The iDRAC on this box (pre flash) used to show seven out of the eight disks as "secured", I wonder if there isn't some lockdown that Dell has in place that ensures genuine disks or something similar.