if it were del or bom then i would be more comfortable trying something like this....maa is a small airport so there are chances things could go wrong....

typically, with online boarding passes, you have to get them stamped at the airline counter before you are allowed to board....not sure you can get that done in the transit area....i know someone who faced this problem in del while trying to transit to sin without an indian visa....

if all goes well then you should be able to go to the lounge area quite easily....the lounges are right next to the boarding gates so that won't be a problem....