Are there any possibilities of changing fonts, font family, font style(bold, italic, etc) and weight using omni.ui ?
You mean in your OWN kit app or in USD Composer ? No for our kit app. For yours yes if you want to by loading in fonts and changing the kit code. But I would not advise. Why are you looking to change the fonts ? We work hard to make the UI very readable. Make sure you try to use it as 100% windows font scaling