Short answer none..... Those templates dose not add HD…. And there fore no feats, skill points, caster level, ect….
Long Answer all template are rough guild that you lay over monster base to make them better or weaker. The base monster you where looking at was CR 3 with 4 hit dice. The two templates are both +1 CR. Then CR 3 + CR 1 +CR 1 = CR "5" Posed CR.
But after you advance, devolve, add treasure, Hit Dice, and or Class levels extra to any monster you need to look at table 1-1 on page 291 of the Bestariy. To figure if it posed CR result is in range of what CR should be for a monster. There is 10 thing to check if net change is + -or 3 then leave it alone if + -or 4-6 the change it by 1 CR if + - or 7 or more then change it by 2. What ever direction the +- sign is.
The CR system is a guild and not perfect. All CR 5 are not the same toughness some are stronger some weaker. Advancing a monster is an art not a science.
The other day I add 2 level of Barbarian to Worgs which should add +2 CR but, after I add the levels the stats modifer for class levels change for add Class levels and NPC wealth to them for equipment there where to strong. So I made +3 CR. And that was still a rough guild.
It still 5th level Driud so it CR 4.
NPC class are levels -2 PC classe levels - 1 CR.
But you still need to acount for base pet. It CR that of base monster.
Any thing that makes it better is accounted by druids CR.
I Give CR spell that precast that have an effect of the combat.IE if got 3 level one spells the that 3 CR 1 EXP if they effect the comabt.
And at 5th level druid can only wild shape into small size or meduim not large. At 6th level it can go in to tiny and Large.
Unless otherwise noted, polymorph spells cannot be used to change into specific individuals. Although many of the fine details can be controlled, your appearance is always that of a generic member of that creature's type. Polymorph spells cannot be used to assume the form of a creature with a template or an advanced version of a creature.
Wildshape emulates the various polymorph spells, with a few exceptions. None of these exceptions preclude this rule. So, barring a houserule, you cannot assume the form of a templated created using Wildshape.
As a houserule, you might look at the table in the back of the Bestiary showing how many HD a creature of a particular type has for a given CR. For example, a CR 8 magical beast should have 10 HD (give or take), while a CR 9 magical beast has 12 HD. So, if you were to add a +1 CR template to a CR 8 magical beast, it would be worth roughly 2 HD. This gives a variable value for +X CR templates, which is reasonable since several of them (half-dragon, half-fiend, half-celestial) offer variable benefits based on HD.
The problem with a blanket CR +1 = 2 HD is that it doesn't match at all with how the game works.
First, the polymorph spells are based on HD, but rather size and the various abilities gained. If you want to assume the form of a 38 HD medium sized animal - if you can find one* - at level 4 (when you can start wildshaping), you are welcome to. However, you only gain a +2 Strength, +2 natural armor, an alternate move speed up to 30 feet, darkvision, low-light vision and/or scent in addition to the natural attacks of the creature (though not any of the special abilities on those attacks).
Also, not all templates are created equal. First, the Advanced template will do nothing for you, since the spells emulated by Wildshape determine the ability augmentations you can assume. Also, the level of the spell determines what size creature you can assume, so using the Giant template will likely give you an inferior creature (with less hit dice and generally worse abilities) that is of the largest size you can use based on the ability's level.
You also run into shenanigans with things like applying the Young template to creatures to gain the ability to access them earlier (since Young reduces the creature's size making it fit into a lower version of the polymorph spells). This could be a cheap trade off if you weren't assuming a certain form for the combat prowess, but rather the special abilities. It's probably not super-broken, but it does open the door for abuse.
Applying Celestial/Fiendish gives you additional abilities...which aren't included in the abilities you can retain while in the form of the creature via the polymorph spell, so you gain nothing from those.
Half-Dragon/Celestial/Fiend templates are, as discussed, worth variable amounts based on the creature's number of racial hit dice. Making them worth a blanket 2 HD doesn't really accurately measure their value. Also, taking on the form of a Half-Dragon requires access to Dragon Form X, since the type of the creature becomes dragon. With Half-Fiend/Celestial, you could never assume those forms, since there is no "Aligned Outsider Form X" spells. (The only outsiders you can currently assume the forms of are elementals.) Lich, skeleton, skeletal champion and zombie are also templates, but since there is no "Undead Form X" line of spells, you could never assume them (unless you want to write up some well balanced Undead Form polymorph spells for your casters to have access to as well).
Leaving you with just the Giant template...which really isn't worth it, since you can just assume the form of something of that size (if you are gaining it for the reach or STR/CMB/CMD bonuses) or you can select another creature with similar abilities of the requisite size. With Bestiary II out, you aren't really want for creatures of which to assume the forms.
In short, you can do whatever you'd like in your home games, but I would encourage against this. It doesn't work. There is a reason that the fine folks at Paizo who crafted the game chose to disallow templates when polymorphing. They did a lot to nerf polymorph so that every druid doesn't become a Fleshraker Dinosaur or whatever uber-powerful critter happens to crop up in a source book somewhere.
*Note: this creature will never exist.