It would have been better to write
"I am unsure of #3, because we are talking about lawyers. I want to say 'whom', but I'm pretty sure the answer is 'who'. And yes, I can start that sentence with 'because', (and this one with 'and'...)"

Although sentences beginning with "and," "but," "or," "because," or "plus" may be used informally, use a suggested replacement for a more formal or traditional tone. (Not that there is anything wrong with that. Not my place to judge)

I think you're right, but I deliberately started the sentences that way because it's a thread about grammar and I was taught not to start sentences with 'because' or 'and'. I thought it was rebellious, and I'm nothing if not a grammar rebel...

I hope you have that emblazoned on a leather jacket.

I don't, but I kind of have to now, don't I? Too good to pass up!

Yo It's aight. ah'm nahh longer git stressed out 'bouthavin` ta take uh course 3 times just so ah can communicate wif peeps what 'chew trippin foo'

Rebel without a clause

Yes I can! I am so smart. S-M-R-T.

I drove to the store and bought two eggs too.