"1. I have problem with both front panel 3.5mm jack socket and motherboard 3.5mm socket"
is this a physical problem(broken/damaged) or you are having issues using them ? (probably driver related)
USb adapters will depend of your country in this world, where do you live at ?
I use Creative labs T30 Speakers, then I plug my headphones to it when I don't want to plug it in I get speakers.
https://www.amazon.com/Creative-Wireless-Bluetooth-Computer-Communication/dp/B00EVWX8R0/ref=sr_1_3?s=electronics&ie=UTF8&qid=1518698723&sr=1-3&keywords=creative+speakers+t30&dpID=41I6tZ-%252B%252BRL&preST=_SX300_QL70_&dpSrc=srch
I use an older USB/3.5" adapter (mic/sound out) and it works great.
Surround Gaming Headset USB To 3.5mm Jack Stereo Headset Adapter : https://www.amazon.com/OEM-Part-GenuineLogitech-Surround-Headset/dp/B00PZC792K/ref=sr_1_11?s=electronics&ie=UTF8&qid=1518698660&sr=1-11&keywords=logitech+USB+to+headphone