1 ) does this have a 3.5 mm jack for headphones ( to make calls with )
Yes. In addition it has a bluetooth earphone to make phone calls as well.

2 ) what kind of speakers if any does it have, must headphones be warn to listen to something, music, videos, a recording, a call ?
It has speakers built-in, so you don't need headphones to listen to music, videos, or make a phone call.

3 ) what kind of warranty does this product carry ?
1 year factory warranty. You pay the shipping cost. For more details, please check our website uPlayTablet.

4 ) if repair is needed, must it go back to China or just California ?
Back to China, but you only need to mail the tablet itself using USPS Priority Mail small box, cost about $13.95.

5 ) I intend to use this unit with a TMobile reseller, so using the
tmobile GSM SIM based data & voice network no problem right ?
No problem on T-Mobile. We have also tested AT&T as well.

6 ) Lastly, I can't seem to find any accessories for this unit.
- Such as a silicone skin, or other protective options,
It comes with a leather case.

- such as a protective film for the screen.
It comes with a protective screen.

- do these protective accessories exist for this device.
As I said they are included in the package.

7 ) Con you confirm the spec? - 1g ram, 4g mem, 1g processor, b/g/n

It has 1GB RAM, 4GB flash storage, 1GHz Qualcomm CPU, and supports WiFi 802.1 b/g/n.