Ready to start after rebuild

[flouese]

My motor replacement took such a long time (3 months) due to being in the rainy season and work, I am finally ready to try and start it (2.5L) for the first time. Full of fresh oil, replaced transmission fluid, brakes bled, master cylinder replaced.

Only issue I currently know of is my post cat O2 sensors are not connected since the replacement cats do not have a bung to insert the sensor. Will this be a problem with startup? My intentions are once the car starts take it to a shop that will install the bungs in the proper location.

Are there any tidbits that will save me a lot of aggravation and frustration after I turn the key for the first time?