Speaker confusion

So I have always more or less stuck with the stock speakers/head unit in cars I have owned but recently purchased a Pioneer DMH-2660NEX head unit because I wanted Apple CarPlay. I have a 2015 Prius V Two. After installing the head unit I noticed just how bad the stock speakers are and decided I would upgrade those as well. Here is where my inadequate knowledge of car audio comes in.

I happened to find a 2011 Prius in a junkyard with the JBL audio package. Someone had already taken the head unit and amp but all of the speakers remained. I grabbed the dash, front door and 6.5" rear door speakers. I figured for $30 these junkyard speakers would sound better than the stock until I save up and purchase better speakers. I installed the door speakers and they do sound much better than the stock. The dash speaker uses a different connector with four wires while the JBL from the 2011 Prius has four wires. I don't know the first thing about soldering speaker wires, capacitors, etc. so I plan on purchasing dash speakers.

I stopped into a local Best Buy to see what they had (nothing that would fit) and the salesperson told me that I needed to match the ohms to the door speakers. I've searched and can only find one page that mentions the ohms of the JBL speakers (1.8 Ω 28 W front door, 1.85 Ω 40 W rear door, no info on dash speakers). So according to the user manual my head unit has a Load Impedance Allowance of 4 OHM with 4 OHM to 8 OHM allowable.

If the JBL speakers I installed in the front and rear doors are actually 1.8 ohm and 1.85 ohm am I risking damage to the head unit? And if I'm to match the dash speakers to the doors, should I be looking for speakers around 2 ohm?