Roth IRA conversions

Hello! As a little background, I am ineligible to make Roth IRA contributions or deduct traditional IRA contributions due to my married filing separately status. I learned this before filing my taxes for 2019 and recharacterized my 2019 Roth contributions as traditional contributions. I was told by financial institution that I can still contribute to a Roth IRA by doing a conversion. I have three questions on this.

 

1. Can I convert my recharacterized contributions (ones originally made in 2019 as Roth and recharacterized to Traditional) back to a Roth IRA? 

2. My understanding is that because my Traditional IRA contributions are non-deductible, I only pay taxes on earnings when I convert. Can I contribute money to my Traditional IRA account, convert it to my Roth IRA account, and then purchase shares? Or do I have to purchase shares first and convert those? I want to avoid accidentally making a direct Roth contribution.

3. Do I pay taxes on any converted earnings on my yearly tax return or sooner?

 

Thank you all!