r&r cluster, now it won't start, need help

Here's what I suggest you try... Reach over the steering wheel with left arm grab the column shifter and pull up hard, turn the key. If that doesn't work, take the shifter to neutral and move it slowly up and down in the neutral range/area while the key is turned to start position.
I'm betting it will start. If I win the bet, You'll need to crawl under the car and adjust the shifter linkage. Maybe not today but eventually.