He requires:
An Alignment;
Two feats that are easily picked up;
Base saves in Fort and Will of +3, also easily done;
And skills.
So the only problem is the skills.
Skills
If a skill is a class skill for any of a multiclass character’s classes, then character level determines a skill’s maximum rank. (The maximum rank for a class skill is 3 + character level.)
So, if your first level is in Savage Bard, you have it set the maximum scores in all of those skills. Granted, if the skill is a cross-class skill for the level you're taking, you still need to spend 2 points per rank.
Ur requires: Bluff 6; K. (Arcana) 5; K. (Planes) 5; K. (Religion) 8; Spellcraft 8.
All of which are Savage Bard skills. Thus, so long as you have the skill points to spend, you can raise it to the appropriate ranks at level 5 for K. (R.) and Spellcraft, and earlier for the rest.
To enter Ur priest at level 5, you'd need Primary Contact on two skills. That isn't possible, thus there is no entry into Ur-Priest before your 6th level (without using broken interpretations of bloodlines).