Note that your expenses will increase with inflation, so you should subtract expected inflation from any expected interest rate. E.g., if you assume 3% inflation then you would use 3.6% and 4.7% respectively for VBIAX and VTSAX.
I agree with most of the rest of what you wrote, and in general you are correct that you need to account for inflation when projecting things forward over longer periods of time or in high inflation environments, but for a YMOYL wall chart in the US right now you would not need to subtract off inflation. The answer varies depending on who you believe:
1. If you believe the author of YMOYL, then inflation is either non-existent or can be combatted indefinitely with creative savings approaches, such as moving to a less expensive country or living with friends. I have heard this didn't work out well for him, but that's what he thought.
2. If you're using 4% as the rate (which is what I do, BTW), then that rate accounts for the effects of inflation already. Subtracting inflation would be double-counting it.
Also, the wall chart is a graph of current income and current expenses over time compared to investment income over time. One would expect these three lines to increase at wage growth, inflation, and investment growth over time, so they'll all be exponential curves (although for me, the income line is very jaggedy because I plot it on a monthly basis and my income varies from month to month). If you just eyeball it, you'll be able to pretty much take a pencil and graph it forward to project the crossover point (or you could do a exponential best fit in Excel).
If I were OP I'd use 4% for the Roth and 403B accounts. For the pension I'd probably just add the monthly pension amount to the investment income amount. So for example, if OP had $100K in the Roth and 403B, and would get $300 a month from the pension, I would calculate monthly investment income as:
($100K * 4% / 12) + $300
which would be about $633 per month.