Is that quotative 「と」 + 「か」 for indirect questions?
I'm not sure how to translate this sentence. I know that similar questions already exist but I don't understand the meaning of this particles before the verb 「待ち伏せる」.
「か」 as you may know is a particle that shows uncertainty, usually to create a question. Here, even though it is not what we call in english a question, it acts like exactly like it.
「と」 is the quotation particle. A quotation is not necessarily marked with a quotative verb such as 「言う」, 「伝える」, 「思う」 and all, but it is always implied even though we don't necessarily think of it.
「かと」 can be seen as a combination and the meaning of it depends on the verb that follows, with a verb like 「心配する」, 「かと心配している」 would mean "I am worried whether...". As you see, I translate the 「か」 into "whether" to express uncertainty. As for the 「と」, you can imagine the verb 「思う」 in between 「と」 and 「心配する」 to make it easier to understand.
死んだかと心配してる。 = I am worried whether he died (or not).
死んだかと(思って)心配してる。 = I am worried (thinking) "did he die?".
The verb implied is not always 「思う」 though, it can be 「する」 as in:
ドアを開けようと(して)口を開いた瞬間... = At the moment I opened my mouth trying to open the door... (from ゼロから始める異世界生活)
Anyway you get the point. As for your sentence, here is my interpretation:
出口で不審な人物や娘が出てこないかと待ち伏せた。 = I layed an ambush thinking "aren't a suspicious character and girl going to come out" at the exit.