If the jars sealed, you are good. keep an eye on them to make sure they stay sealed due to possible sauce in the seal. Re process if in doubt about that.
The temperature of the sauce going into the canner isn't really relevant. Everything warms up during the 10 minute venting process and subsequent building to pressure before starting the timer. Just be sure the steam column is good and strong for 10 min. The steam can be hard to see and rate so venting an extra 5 minutes won't hurt.
The siphoning is much more likely to have been caused by inconsistent pressure during the actual timing process.
Not letting the canner quite cool enough before removing the lid and/or the weight. Give it at least 10 minutes after cooling down to 0 pressure.
Occasionally, siphoning can happen due to incorrect tighting of the lids but it's not much of a concern.
#1 cause is usually, not enough head room