Roaming has become a popular addition to the metagame strategy, wherein one player does not lane nor jungle, but rather simply moves through the jungle/river to initiate ganks on lanes from level 1 and onward, until the teamfight portion of the game begins.
A roamer essentially guarantees that you're either running a solo lane, or two solo lanes if you have a roamer and a jungler. I've also seen a double roamer game played, though this tends to be less effective as enemies who are wise start playing defensively and reduce the effectiveness of your roamers, which put them behind in both CS and levels.
The qualities of a roamer can vary, but the general requirements are that they are mobile, can do burst damage, and have a strong stun or position altering (push, throw, etc.) ability. Taric, Evelynn and Alistar are all very popular choices for roaming. I've also seen Sion and Blitz play roaming effectively, but they were both out of a lack of a jungle spot on the team and normally suit better in a lane.
This strategy is similar to the "double jungle" mindset in that you get three solo lanes, with the exception that there is extra pressure on getting early kills to succeed. A definite risk vs. reward tossup, as successful roamers will quickly catapult your laners ahead in level / CS as well as demoralize your opponents, but unsuccessful roamers will fall just as far behind due to the lack of their presence in the laning phase.
As for a Veigar vs. Morgana lane. You, as the Veigar, should never even attempt to harass her. Farm farm farm. Level your Q to three or so for effective lasthitting, and after that W for effective Counterpushing against Morgana. Hope for a better lategame, as If you've farmed well enough, you can crap on her with your burst. Also, focus in the early-midgame on heavy lane ganking, as your stun is one of the longest in the game.
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Here are some facts about the various abilities:
Yorick's Ultimate Omen of Death: Omen of Death has the lowest priority in terms of revival because it does not resurrect the champion, only revives them temporarily. This means that if an ally were to die while under the effects of Zilean's Chrono Shift or Guardian Angel as well as Omen of Death, the champion would be affected by the one that prevents death.
Zilean's Ultimate Chrono Shift: Chrono Shift will always take precedence over other revival abilities, like Guardian Angel and Rebirth (Anivia's passive).
Mordekaiser's Children of the Grave: If Children of the Grave kills a unit affected by Omen of Death, then Yorick's ultimate will trigger first.
So, Chrono Shift has the highest priority. Next would be Yorick's Omen of Death, followed by Mordekaiser's Children of the grave.
Rift Myths has a video of the interaction with Mordekaiser and Yorick ultimate:
Note that Mordekaiser got a ghost because he killed the Yorick ghoul before his ultimate had timed out.
EDIT: KaelVonrik correctly points out that Mordekaiser's ultimate would be removed at the champion's death, then the champ would be revived by the Zilean's ultimate. So, no Mordekaiser ghost would be spawned. So Mordekaiser would need to use his ultimate after the revive by Zilean, but can cast it once Yorick ults as long as he kills the Yorick ghost before it times out to finally receive his ghost.