The budget reconciliation process is being led exclusively by Democrats and can be passed with only Democratic votes. Because of the tight margins in both the House and Senate (they can lose no more than 3 votes in the House and none in the Senate), and the diversity of perspectives within the Democratic Party between progressives and moderates, it will be a challenge for Democratic leadership to finalize legislation that enough lawmakers are comfortable with such that it can pass both the House and Senate.
The policies that Democrats are pursuing right now establish a progressive negotiating position. Different committees are pursuing different policies within their respective jurisdictions without serious regard to most moderate Democrats' concerns. The overall expected cost of the policy changes currently being pursued is apx. $3.5 trillion. It is expected that once each committee addresses the items within their jurisdiction, House and Senate leadership will negotiate this number down to something closer to $1.5 - $2 trillion.
NATSO provides an overview of what each committee is working on. If the reconciliation passes, it will very likely leave out at least some of the items discussed below, and scale back the cost or duration of some programs as part of that House-Senate negotiation process. That being said, it's not unlikely that Democrats will find a way to pass much of this into law.