Also does it matter if I install 32-bit apps after the 64-bit is on system or does it matter?
You should have no problems running your 32 bit apps.
One thing, if your 32 bit app has a 16 bit installer you will not be able to install the program. 16bit programs will not run on a 64bit system.
You may be able to install them on a 32 bit system and copy the program over to your 64 bit system but if the program writes to the regestry during install you will run into trouble. Mostly the only programs that have 16 bit installers are old and out of date anyway.
You can check
here if you have a program your unsure about.