Heh
Ok. That was a longish post with quite a few questions
Realex offers more than one integration option. In the "simpler" method (remote) you get redirected to Realex's servers to make payment and you (the developer) can customise the look and feel to fit in with your main site.
As for SSL or no SSL.. If you are going to store ANY personal info on users I'd recommend considering SSL regardless of how you handle payments. The feelgood / comfort factor should never be belittled / undervalued