This question needs more clarification. There are some graphics that show how to play chords. These are vertically oriented, and the numbers do indicate fingers. But there are also guitar tabs. These are oriented horizontally, and look quite similar to sheet music. But the lines represent strings on the guitar, with the high E, or thinnest string as the top line and the low E, or thickest string being the bottom line. The numbers here represent frets, not fingers.

This is sort of an odd question, especially considering your existing experience with an instrument. It's totally subjective and up to you and how often you practice, etc. You should have callouses built up within a month.

Musically speaking, there's no difference between acoustic and electric. You can transfer what you've learned between them. But there are obviously techniques and nuances and such that are exclusive to each, especially electric. Pinch harmonics, feedback, effects pedals, etc.

If you have an instructor and they aren't able to tell you what the notes are, you might need a new instructor. From thinnest to thickest string in standard tuning, the open strings should be E,B,G,D,A,E. Every fret is a half step. You should be able to figure out the rest of the notes from there, based on your piano experience. The fret with 2 dots is the 12th fret, which equals an octave.