Thanks to all! I wasn't expecting the learning curve to take so much time. But so far its running well. I use a Parrot Bluetooth dongle. Bluetooth set up seems a bit odd though.
Mainly the credit goes to mechdrew, New Part D: External DVD Drive Installation, meklort & bmaltais.
Here is what I did:
I first booted with '2' pressed to get into the BIOS Setup Utility;
then went to Advanced, set USB BIOS Legacy enabled, USB Wake Support Disabled, WLAN and Bluetooth Enabled along with the rest of them enabled.
Then on to Boot, made certain Hard Drive was first; CD/DVD was second. Then fn10 to save.
But to make certain drives were where I would want them after the install, I pressed the 0 before closing out with the Enter key. That brought me into the one-time-only Boot order window next. I made certain the CD/DVD drive was highlighted, then holding down the 0 (just to make sure), I closed out.
The DellMiniBoot123v8.01.iso.ran ok. Swapped for the 10.5.1, then it hung up. I fiddled the CD/DVD cables in and out and it began to load very, very slowly. But I could eventually get to the Disk Utility, do the GUID partition and continue the 90 minute, endless slog. Also, OS 10.5.1 didn't like my USB drives. So I did everything with CDs instead.
Turns out the problem was my OS Retail disk was 10.5.1. There was no way it would let me boot to the new GUID Hard Drive partition even though it had beeen named when I did the Disk Utility GUID Partition. Tried five times and then figured it must be the old retail 10.5.1 disk. Moreover all was stretched and ugly and I didn't care to mess with the Apple UpDate to 10.5.6 problems.
So I drove 30 minutes in the blinging rain to the Apple Store and bought the new 10.5.6 disk.
I figured I scrambled about everything, so ran the DellMiniBoot123v8.01.iso. again, swapped it for the new OS 10.5.6 disk, unplugged the USB and turned the power off and on, replugged it, followed the prompt instructions for f9 and the DVD spun up, lights and all (OWC Platinum Samsung). The silver Apple logo was stretched, but the rest not - except for the tiny spinning grey gear, but I can live with that.
Once the Disk Utility was available I checked again to see if my Hard Drive was petitioned and named as I had intended. It was, so I continued the install. About an hour.
I then plugged in an USB drive with the DELLEFI1.07, ran it. Then rebooted on the retail OSX 10.5.6 disk so I could choose the Hard Drive as a start up. Restarted and it booted off the 32 GB Dell Mini Hard Drive. Then I ran the About This Mac off from the USB where I had the pkg. The rest was pretty much MAC.
Everything works, including WLAN and a Blutooth dongle I inserted, though the set up is a bit irregular. Seems to me somebody wrote about that.
The grey apple logo after the Dell screen is bloated, then after OSX10.5.6 loads,all is in correct proportion.
The system hangs if it sleeps, so that a restart using the button is necessary. If I change the Energy Saver in Preferences to Computer Sleep Never and leave the Display Sleep at 5 minutes, will that help?
1) Any way I can get rid of the ugly Dell and Terminal stuff at start-up before Apple starts up?
The Apple logo was stretched from DELLEFI1.07. meklort sorted this perfectly with DELLEFI1.2a5.
I don't think I botched this report, but may have. If there are mistakes in my recollections of the process, please let me know and I will edit.
Thanks again, cas