I am remodeling my bathroom and have some questions.
1. I have an outlet running to a 20 amp gfci breaker. I have replaced the outlet with a 15 amp outlet and ran another wire to the hallway from this outlet and connected a 15 amp outlet. Is this okay?

2. I am also removing my old baseboard heaters. I wanted to install an outlet where the heater was using the old wiring. It is 12/2 wire going to a dual pole 20 amp breaker. What amp breaker should I replace this with and what amp outlets should I use?

3. This question does not involve the bathroom. I want to install a ceiling fan in my living room that is on the first floor. (no attic access) I was hoping to again use the wiring from a baseboard heater that I will be removing. Question again about the circuit breaker that I should use? Also can I put a junction box in my crawl space to make the wire long enough to reach the ceiling location?

Thanks in advance.

My answers are in bold.

1. I have an outlet running to a 20 amp gfci breaker. I have replaced the outlet with a 15 amp outlet and ran another wire to the hallway from this outlet and connected a 15 amp outlet. Is this okay?

Yes.

2. I am also removing my old baseboard heaters. I wanted to install an outlet where the heater was using the old wiring. It is 12/2 wire going to a dual pole 20 amp breaker. What amp breaker should I replace this with and what amp outlets should I use?

Since you have #12 wire, use a 1 pole 20 amp breaker.

3. This question does not involve the bathroom. I want to install a ceiling fan in my living room that is on the first floor. (no attic access) I was hoping to again use the wiring from a baseboard heater that I will be removing.
Question again about the circuit breaker that I should use?

Either a 15 or 20 amp 1 pole breaker. Again, since you have #12 use a 20 amp breaker.

Also can I put a junction box in my crawl space to make the wire long enough to reach the ceiling location?

Yes, as long as the junction box is covered with the proper plate for the box, and the box will always be accessible.

Regarding #2... you will take the black from the existing 2 pole breaker and install it in the new single pole breaker. The white that was installed in the existing 2 pole breaker will be relocated to the neutral bar.