when orianna uses her legend power to turn a gear into a unit, can I now equip equipment to it, and does it gain the effects on those cards. Example use oriannas power to turn ball into a unit, equip guardian angel to it, GA dies instead of the ball?

Radiance rules aren't published yet. This uses the printed card and current rules only, and it isn't a ruling on the new mechanics.

Yes — you can Equip an Equipment to The Ball once Orianna has made it a unit gear, and GA's Effect Text does apply to it.

Once it's a unit gear, The Ball is a Unit for targeting purposes (Rule 178.1.a.1), so Equip's "attach this to a unit you control" can choose it. When Guardian Angel attaches, The Ball becomes the Top-Most Card and GA's Effect Text — the part below the Equip line — is appended to it (Rules 136.2.c, 718.3). So your example works: if that ball-unit would die, GA's replacement effect applies instead — kill Guardian Angel (it detaches and goes to trash), heal the ball, exhaust it, and recall it to base. GA also adds its +1 Might bonus to the ball while attached.

Two caveats. GA's own printed Rules Text (the Equip line) goes Inactive while attached, so it can't re-equip itself. And Equip is a normal activated ability — your Main Phase, Open State, not during a Showdown (Rule 151.2) unless the gear has Quick-Draw. Also note the Radiance overview's "when an Equipment becomes a Unit, it's automatically unequipped" line covers the reverse case (turning GA into the unit), not equipping a gear-unit. This is my interpretation based on the Equip/attachment rules; no official FAQ exists for this specific interaction.