OK, read through the information on the
US2Canada website about spousal sponsorship - that's the best avenue for you to apply to immigrate to Canada. However, if you still have a DUI and/or theft conviction(s) on your FBI clearance, you'll need to
apply first for rehabilitated status or they will find you inadmissible to Canada and refuse the PR application. Whatever you do, with a history like yours, don't apply inland - even if you
can get into Canada to visit. There is no requirement, even if you're staying in Canada whilst waiting for PR status, to apply inland and you preserve your sponsor's right to appeal a refusal if you guys
submit an outland application. No advantage whatsoever to an inland ap for a US citizen even in the best of situations, but in your case, it could end up costing you years and then an ultimate refusal anyway with no right of appeal and you'd have to leave the country immediately.
Best favour you can do for yourself is to either make sure those convictions aren't on your FBI (or any State) report, and if they
are, take care of them properly
before you apply for PR - either by applying to have them expunged (if that's an option), or by getting "deemed rehabilitated". If you get into the PR application process before resolving those issues, it's going to take years and you could set yourself up to not even be able to visit Canada in the interim.
Another option that might have merit is to
apply for a Temporary Resident Permit if it turns out that you have convictions that can't be resolved through other means. A TRP allows you to come to Canada to live and work even though you are inadmissible and is issued when there are sufficient humanitarian and compassionate considerations to allow you to come anyway ("best interest of the children"). After three years in Canada, "keeping your nose clean" on a TRP, you'd be eligible to apply for PR and your inadmissibility would no longer be an issue. In the meantime, if your inadmissibility was overcome through other means (like the "Deemed Rehabilitated), you'd be able to move forward and be sponsored even before 3 years.
This is just a general opinion and description of how to proceed that I've gleaned over the years after having my outland PR ap refused because my non-accompanying dependent had a conviction. I was documented on a TRP on H&C grounds until our appeal could be finalized - so I have a bit of an understanding of it. But you should probably consult with a qualified Canadian immigration attorney for more information before you make a decision regarding how to best move forward.