2.7L 2 Cats to Universal Cat replacement, heat shield

hello mother sons and daughters,
my thought is that the 2 oem catalytics have different metals that act differently on the exhaust. can I get a universal cat that fills both roles? and that universal cat is small enough to fit under the heat shield under the passenger butt?

2002 cali extended cab with 2.7l

thank you, spare tire

 

May not pass cali emmisions inspection. An inspection location or shop could answer that for you.