I can only help you with one of the things you asked for. To hide the default search bar, follow these steps:

Press Alt P to enter opera's setting Move cursor and press left mouse button on a blank area so there is no "I" bar in the "search settings box" Using the arrow keys using this combination ↑↑↓↓← → ← → b a You now see a box pop up that says "power user settings". Click on "I understand, proceed" button. Scroll down to "Start Page" area. Place a check mark "Hide the search box in Speed Dial"