Retroactive contribution disqualification in Self-Directed IRA

[Steve K.]

You all may know that you can make ROTH IRA contributions for year 2019 until July 14th 2020. Contributions can also be made for 2020 as well.

2019 - We are about to make those contribution in 2019. Since our MFJ MAGincome for 2019 was significantly lower than the IRS limits., we're eligible.
https://www.irs.gov/retirement-plans/plan-participant-employee/amount-of-roth-ira-contributions-that-you-can-make-for-2020

We also would like to make 2020 contributions asap but have some questions:-
1. If contributions that have already been made for the current calendar year, can they be retroactively disqualified if MAGI exceed $196K for that year? If yes, what are the penalties and taxes owed to the IRS?

2. What do you suggest for someone, if their income is expected to exceed $196K. Should they open a traditional IRA and do a IRA to ROTH IRA transfer to avoid running into this scenario now or in the near future? From what I read, it looks like funds have to held in traditional IRA for about an year before it can be moved to ROTH.

I asked the above questions to a service provider that I'm currently doing business with on this forum. Their reply was generic and asked me to call my accountant and I did. My accountant doesn't specialize in IRAs and told me to wait until Dec 31th 2020 to make contribution. I immediately jokingly told him that his advise was useless (We have a great relationship and my accountant has proven his worth over last few years).

The service provider from this forum also said "If you think that you will exceed the limits, then you can deposit into a Traditional IRA and then convert to a Roth IRA (no waiting is required). You will certainly want to coordinate with your tax advisor to ensure proper reporting and consider the pro-rata rules"

I am NOT SURE, what does pro-rata rules means? (Read above for context)

Does anyone know IRS publications that I can read for this situation? 

Can you refer me to someone on this forum or outside who may have answers to my questions?

Thank you!