ok i dont know if a fully understood what your asking...
for a 2g or anything around that size you dont need a filter at all, its merely up to you and your preference but it WONT change water changing habits IE. with a 2g its 100% twice a week. a heater is always recommended if your not living in hot climats.
a 10g is a nice tank for a betta and you always have the option to divide for another male or female. water changing for a 10g uncycled is around the 50% once a week and 100% every 3 weeks or so. for a cycled 10g its around the 30% per week.
you should really hold off breeding for another while. its not easy, and you will have to plan accomodation for anything up to 300 fry.... even some of the pro's on here dont breed because its not all fun and games...