These are indeed good points. A ship appearing to take forever to reach the speed of light, would be consistent with time dilation rules - the faster you go, the slower the time flies in another frame of reference. But that doesn't mean said ship is not speeding up.
By the way, acceleration and relativistic speeds are not about "magic". Shrinking ship and a ship that, paradoxically, slows down as it accelerates is just a question of how light is being reflected off such an object.
Precisely because of that, you will not even be able to see an FTL object because its image (meaning the light it reflects) would reach you far long after the object has already passed by!
But... we're sort of diverging from the main topic of this thread which was an ET life...
For one thing, I think that it is impossible to believe that ET have already visited us accepting, at the same time, the notion that FTL travel is completely impossible. Otherwise, how would they even reach us in the first place?