It should be good. -PU is the packaging, in this case 28 PDIP, the one that can easily be used with a proto-board.
16 is probably the max frequency in MHz
Regarding the 8bits, roughly speaking it means that the MCU can manipulate 8 bits data / instruction. Like perform
an addition of two 8bits numbers in one instruction. You don't have to worry about this, all atemga8 are 8bits as well as
most MCU people are using here (like the one on the Axon for instance).