Hi Dave...
You have gotten some very good answers to your questions...and it's true, this is an impossible question to answer because of all the factors that contribute to a fig tree's growth.
Containerized trees vs. in-ground cultivation will give you completely different results under the same conditions. Containerized trees will be self-limiting, and will never equal in-ground trees. They also require constant attention on the part of the grower, and cannot be neglected. No vacations, etc...unless you can get someone reliable to tend to your trees.
However, what method of growing you chose will depend on your goals. Do you want very large trees...or, do you want easily managed trees. You originally asked about growth rates so that you can judge/compare the trees that you are growing to some "standard" yardstick. We cannot answer this. Too many variations in growing conditions make these predictions just a guess, but you should get at least 8"-10" of new growth each season.
You live in Zone-6. Your winter temps. will be a huge factor influencing the ultimate height/spread of your trees. If you plant a "Black Mission" tree that could grow to 30ft. tall...but, is killed to the roots each year....why will it matter? Few places in the USA have climates in which a fig tree can reach its genetic potential. Everywhere else is a hostile environment for a fig tree. Ultimate growth rates will depend on how you good you are at minimizing the things that will kill your trees.
*By the way...your soil is too acidic... Fig trees hate acidic soils. top-dress to roots/dripline with a couple of good handfuls of granular limestone. Too much acid leads to low production, poor quality fruit, diseases, and weak trees. SEE BELOW.
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*********(EDITED COMMENTS/CORRECTION....Please disregard this comment. Your soil is not too acidic...my pH memories have failed me, and a sharp-eyed forum member pointed out my error. Thank-you Centurion! Sorry for not being accurate and for not fact-checking before I posted this wrong information). That being said...keep in mind that chemical fertilizers will turn basic soils to be more acidic soils, so it can't hurt to top dress with granular limestone anyway.
Good luck...and your questions are not "stupid". How will you know if you don't ask? : ) Keep asking!
Frank