First, my father was born a Canadian citizen. He was naturalized as an American in 1990. That's not going to diqualify me, is it? Most intel jobs ask that both your parents be US citizens. I assume naturalization is okay.
As for the SCI component of the SSBI, can anyone inform me on what more is done? Is it simply a longer / more rigorous background check? I know it takes a long time to get, and I'm not particularly worried, but I'm also one of those people who just likes to know what they're getting into.
First off, I'm a CTI2. Second, my sister is a naturalized American citizen, born in S. Korea. When I went to boot camp, they wanted her naturalization paperwork (copies). As for parents, I don't know, but that's what happened with me.
As for the SSBI, it is much more thorough than a regular background check. Various family members may be asked questions; be aware that any person you list as someone you knew during a period of time is eligible...so don't list your ex-girlfriends like I did. When you get 'accepted', you may not readily know, but if you're not you'll know quickly. Also, most SCI clearances require a 5 year re-investigation from the last investigation; also, a polygraph is generally given, with questions about having given away secrets to the enemy and so forth. I had no problem with any of the above, but a number of friends I have had trouble with the polygraph. Don't worry-a lot of time it's just nerves that throw off the polygraph.
Numbers, You shouldn't have any problems. Canada is generally not what the investigators are looking for. Besides, you said he is now a US citizen, so you shouldn't need anything more than his naturalization papers.
When the investigation goes in for a TS, they automatically do an SCI check as well. So when your clearance is adjudicated, you will have "eligibility" for TS with SCI (provided you pass the screening). Your command has to give you "access" to whatever level they need you to have up to and including TS/SCI.
Please do not post anything regarding questions asked during polygraphs on this board. Anyone who has taken a counter-intelligence (CI) scope polygraph should know that they have been instructed not to discuss the test outside of their exam room. What I can say is the CI poly is nothing to worry about.
It is possible to have access to SCI without having to have a CI polygraph; however, it is my understanding that all CTs must undergo a CI scope poly.
All SCI clearances require five year periodic re-investigations, again nothing to worry about. Different agencies have different policies about family members nationalities; generally DoD is the most lenient. As long as family members are NOT officials of foreign governments, you will probably be fine.