Can I replace 15 amp spiral CFL lights in garage with fluorescent lights?
Yes you can replace your spiral lights with 4’ fluorescent fixtures.
A 15 amp circuit can handle quite a few of those 2 or 4 lamp fixtures.
The average 4’ only consumes ~32w or 128w for a  4lamp fixture you could put almost a dozen of those fixtures on a 15 amp circuit.
Consider led, I convert my T8 &amp; t12 lamps to led lamps more visible light and less power usage 15w 1800 lumens but the lamps cost 6.25 ea now.
The advantage to led is more perceived light at the given wavelength using 1/2 the power.
the big kicker is LED’s usually have at least a 50000 hour life and are not affected by turning on and off.
A fluorescent tube has a shorter life and just a month after installing there is a noticeable reduction in light output of placed next to an led.
I even purchase / get for free old fixtures and put LED’s in them
If you do go with LED get DLC certified 5 year warranty with DLC.  Then you could put even more lights up or enjoy the savings while being able to see.