Donating just speeds up things. No donation item is exclusive to the donator so you have no problems there.
For starters, i say stick to one class you can woe with, gear it up using quest item(legendary weapon, legendary gauntlets) and vote items(vote forsaken king set, vote infernal cape), get the necessary cards for most classes (Kiels x3, 2x fbh, tao gunka, ghostring, incantation samurai, turtle general), and then save up for the donation slotted accessories(+40 on one stat, one slot). Once you got two of those you can then choose to get either the donation weapon or the donation cape. I would of course say get either, as the legendary weapon holds up for a while and the vote cape has the same stats(you just cant use it for the quests to get the rings).