16-pin RAM chips: Buffered Grappler Plus question

[sebugg@presby.edu (Stephen Buggie)]

Recently I acquired a BUFFERED GRAPPLER PLUS parallel printer card
with eight sockets to hold 16-pin RAM chips totaling 64K.

Presently just two of the sockets contain RAM chips.  These chips 
have the following  Motorola numbers:

MCM6665BP15
FQQ8516

QUESTION: What Ram chips can be added to these?  I have a number of
these chips:   41256-15

Will these chips work?  Should I remove the two Motorola RAM chips
so that all the chips are identical?  
I read that the speed of ram chips should be uniform within RAM banks.
How critical is this?

I also have some 4164 chips; are these compatible with the Buffered
Grappler Plus?

I would appreciate it if any RAM experts would write an essay on 
how to evaluate the characteristics of 16-pin RAM chips. Thanks.

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 ** Stephen Buggie, 410 Chestnut St., Clinton SC 29325    Apple IIe/IIc **
 ** sebugg@presby.edu                 voice: (803) 833-8337 or 833-1632 **
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