[prmoustache]

Well terminology is important depending on who you are talking to. Some governments may call that trail but riding down a black track at Whistler or Champery is different than just riding along on a non technically challenging gravel road/path. Besides, trail bike is a term used by the bicycle industry for a category of bikes that are much more capable than a cross-country mountain bike on challenging terrain and downhills while not being as much extreme as a Downhill bike with double crown forks which are pigs uphill.

As for your other question it really depends on the kind of e-bike.

Well integrated e-bike from bigger companies have the engine in the bottom bracket area so you can't remove that and the battery is usually so integrated inside the frame. Most cheap e-bike like yours, if it is the same as the one I see on the viribus website, are regular cheap alu frame on which they have strapped a battery on the standard 2 bolts usually dedicated for the water bottle holder cage and the engine is on the rear wheel. So the frame is pretty standard in that regard. Remove the battery and swap the rear wheel for a regular rear wheel and you have a conventional very entry level hardtail.