Definitely not wise. Donate blood when you’re eating/drinking. You’ll be dumping a lot of toxins during a dry fast with some ending up in the blood. People who receive blood aren’t in a state to deal with that toxic load.
I wouldn’t do it. You have something like 8 pints of blood in you. You’re donating 1 pint. That’s 12% of your blood supply.
Eat and drink for a few days after you donate. Or wait until you’re out of your fasting phase before you donate.
No need to tempt fate
You’re looking to give blood, to prevent iron overload, and promote a proper copper/iron?
 
Pretty sure your body will do that on it’s own if you leave it alone…
Dry fasting seems to be where all the stupid people flock… One can fix fat, but it doesn’t seem as if one can fix stupid.