Without Eldritch arcana you are all out of luck when it comes to melee touch attacks. With it you can use intensify your touch spells and make em kinda almost ok-ish maybe. That's as close to viable as you can hope to get. Sorry..
Now obvious problem is there are no AoE touch attacks(apart from kineticist, but I don't think that's what you are looking for). As to stats, you'll pretty much have to be str for more reason than one.
1. Claws don't scale in number of attacks. It will always be 2
2. You can't afford loads of monk levels if you want to go into casting.
So of your requests really only bite stacking is an option for viability and even that will be bit limited as you won't have the option of going majority vivisectionist due to touch attack requirement. So that leaves motherless tiefling and dragon disciple. Unlikely race/class combo, but one can make do.
Instead of just giving you an answer I'd much rather help you with the process of building itself.
Start with the basics.
-4 levels DD are locked // 3CL
-We have to be motherless tiefling.
-with 2 bites there is no compelling reason not to go bite/trip.
-Since we are already tripping only weapon choice is Mastery fauchard.
-magus/sorc as a base class since you need spontaneous caster for DD, need access to touch spells and losing 3 CL and 5-6 levels is not an option, Don't need to go further than that for now.
-armor vs no armor. Using armor makes us a glass cannon for a better portion of the game. And it will mess with your feats. The concept itself is already flawed enough there is no need to hinder yourself with armor.
-With that in mind we can lock in the stats. 18/14/12/10/9/16 will have to do. +4 to str last one to wis.
-That leaves us with scion vs sorc. There is no easy answer. On one hand, scion will provide us with extra feats and weapon enchants. On the other, sorc/EK does the same in terms of feats and actually does also add a way to be using touch spells while using mastery in the long run. magus gives spell strike, so spells won't be wasted, sorc gives more spells to waste...With all that I think Sorc/EK has a slight edge.
-The build I'd go would be Scaled1/Sorc4/EK10/DD4/Fighter1. Or saint1. Compared to a more generic melee sorc we pay 1 level 7 and 1 level 8 spell. Acceptable trade. You need to fit in exotic weapon, expertise, trip, improved trip at the very least and will probably also want fury's fall. Fighter also provides us with 2, but comes at full BAB, so that's what I'd use.

Lvl 1: Monk - Dodge // Crane Style
Lvl 2: Fighter - Fauchard
Lvl 3: Sorcerer - any metamagic feat you fancy(intensify, if you end up using EA) // WF: Fauchard
Lvl 4: Sorcerer
Lvl 5: Sorcerer - Dazzling Display
Lvl 6: Sorcerer
Lvl 7: Dragon Disciple - Outflank
Lvl 8: Dragon Disciple - Toughness
Lvl 9: Dragon Disciple - Crane Wing
Lvl 10: Dragon Disciple
Lvl 11: Eldritch Knight - Combat Expertise // Shatter Defenses
Lvl 12: Eldritch Knight
Lvl 13: Eldritch Knight - Trip
Lvl 14: Eldritch Knight
Lvl 15: Eldritch Knight - Improved Trip // Improved Critical: Fauchard
Lvl 16: Eldritch Knight
Lvl 17: Eldritch Knight - Fury's Fall
Lvl 18: Eldritch Knight
Lvl 19: Eldritch Knight - Crane Riposte // Greater Weapon Focus: Fauchard
Lvl 20: Eldritch Knight

Something like that. Staves till some real good fauchard pops. Just cause you've got the focus doesn't mean you are married to it already. Mastery for late-game. Alignment would be etiher LG or LE(since LN robes are super-late, although is totally possible as well). Ammy slot will be taken by mighty fists, but you should have enough. Rest is pretty standard. Trip feats are kinda late, but there is nothing we can do. We need +4 item for it and those don't come in A1. A pity that we had no slot for social feat, but oh well. Will just have to buff better.

Spells would be something like
Lvl 1: Shield, True Strike, Enlarge Person, Vanish, [Touch spell either shocking or corrosive depending on what you like]
Lvl 2: Mirror Image, Sense Vitals, Glitterdust
Lvl 3: Haste, Rage, Resist Energy(Communal), Vampiric Touch
Lvl 4: Greater Invisibility, Animate Dead, Dimension Door, Protection From Energy(Communal)
Lvl 5: Angelic Aspect, Echolocation, Cloudkill
Lvl 6: Transformation, Heroism(Greater)
Lvl 7: Legendary Proportions, Waves of Exhaustion
Lvl 8: Frightful Aspect

At least you will have some decent use for touch spells late with EK. There pretty much no way to make em good. Damage spells suck in the earlygame. You just have no slots and things don't die to them and you don't have the luxury of resting after every fight. And you sure can't mix bites and touch attacks without EK, cause you need mastery and hence magus dual-casting is out. It's generally either make something with touch attacks eventually or use em early and transition out of them cause magus late-game is spent transformed with no spell-casting whatsoever, so this one kinda has contradictory goals from the outset. I decided to go for the former as the end-result is less gimped and it will slap well, it's a melee sorc, after all. Also you actually don't need low-level spells for anything late. You will have to abuse exp system a bit as described in unfair guide if you want to play with a finished build for longer. One alternative would be some weird scion build that'd use nunchacks and stuff while preparing for fauchard switch in the late-midgame, but then you still face the fact that Magus doesn't do in-combat casting late-game.
Probably is unfair viable, although with 2 AC malus compared to regular melee sorc it might be bit more work.
Main upside is the build is pretty RP-friendly. I could see running something akin to it even in PnP as all classes make sense and stats are decently balanced with no outliers.