First, vis-a-vis optimization and min/maxing there is a quote which applies and that is "if you fail to prepare, you prepare to fail."Second, as far as taking a class of hierophant and losing a caster level, you should try to never lose caster levels so I would not recommend taking a class of hierophant. If you want to take the hierophant class then I would recommend this build: Wizard 1/Marshal 1/Rogue 1/Fighter 2/ Ur-priest 10/Hierophant 5.
For Hierophant special abilities: I don't recommend the divine reach. You should take the spell power special ability for all 5 levels. Take the marshal aura motivate dexterity for a bonus to initiative. Take a level of rogue to give you trapfinding making a thief in the party obsolete. Take 2 levels of fighter for the bonus feats. Then take the Ur-priest (in BoVD and possibly in complete divine.) PrC although you may have to talk to your DM about it as it requires training by another Ur-priest. If you have the BoVD there is a corrupt spell called Power Leech which allows you to enhance a particular ability score. Cast that spell twice and enhance your charisma and dexterity for insane levels of initiative. If you have the spell compendium or magic of faerun, there is a spell called Nerveskitter (also called K's Nerveskitter), it's a level one wizard spell which gives you a +5 to initiative.
For feats take improved initiative plus other feats which you deem appropriate, see guides below.
You might have to work out the details of the above build as it was done of the top of my head.
The marshal class can be found here D&D Miniatures Handbook excerpt.
A clerics guide can be found here The 3.5 Cleric Handbook. If this link doesn't work go to the handbooks page on BG and find the 3.5 cleric handbook, the same with the optimized initiative compilation.
A guide on how to optimize initiative can be found here The Optimized Initiative Compilation.
Otherwise you can take simply take 20 levels of cleric which is actually what I usually do as I think a Ur-priest is weaker than a straight cleric.
Finally, I would not recommend playing a healbot.
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