The inch per fish per gallon is only good for clean water conditions not for good fish conditions. Moreover, if you have teritorial fish this wont work. But your fish dont have teritorial problems (maybe the tiger barbs). Also when considering top, mid, or bottom fish make sure aggression and speed are consistant ie a molly wont mix well with a tiger especially in a smaller tank. a 29 gal is also sometimes confusing because it is basically the same as a 20 long as far as your fish are conserned. Your plecos may be small but here is an example i bought a 2 inch pleco and in less than a year he grew to 11 inches (55 gal) If they are common florida plecos that is, a bristlenose and a few others will grow alot slower.
for a beginner:
danios or barbs make a good start for yeah month or two. (say 3 tops 5)
if desire algae go with a chinese green algae eater
bottom cory cats (like to school as well and many kinds Rare but cool are orange stripped)
a couple striata locahes or other small would work too (not clown or large though)
then pick 2 cool ones you really like groumies or what ever.
just an opinon to help though.
Personally i would go with a colony of cichlid shell dwellers 2 male to 3 female. a couple cory cats and maybe a group of barbs.
Hope it goes well for you. :)