Yes. 

yes. i just bought a SSD for almost 6 yrs old laptop. although the laptop is SATA 1, but can feel the significant improvement of booting and loading application speed.

i use samsung evo 850 120GB SSD.
use ssd as my primary drive.
take out optical drive, bought an caddy to install my existing HDD, this become my secondary drive
and yes, i had sacrifice my optical drive since rarely use it.

er what problem are you trying to solve? the normal process of migration is pretty straight forward. connect your new ssd to your computer via usb adapter. run migration software and start the migration. the new ssd will be detected automatically as target disk. proceed by following on-screen instructions.

you must have turned the hibernation / fastboot feature off. (it's part of ssd optimizations; but it impacts boot speed) you can just turn it back on for fastboot.

in general, each ssd optimization might impact certain parts of your system. it's just a matter of 'give and take'. they should be applied based on outcomes that you need. you don't need to apply the whole thing.