Adjusting Asset Allocation in 401k

Hello all, regarding my 401k I have around $13,000 dollars invested in a passively managed pre-mixed fund that is 75% equities and 25% fixed income, with an expense ratio of 0.06%. For reference, I am 24.
The equities are divided as such:
Stocks:
Large Company Value Index Fund 15%
Large Company Growth Index Fund 15%
International Equity Index 12%
Small Company Value Index Fund 7%
Small Company Growth Index Fund 7%
S&P 500 Index Fund 5%
Emerging Market Stock Index Fund 4%
Real Return:
Real Estate Investment Trust Index 6%
Commodities Index Fund 4
Bonds:
The 25% to bonds are divided into investment grade and long-term government
index funds.

From my own research and the Personal Finance Course/Instagram Page, I have decided to reallocate to a three fund portfolio for the “Majesty of Simplicity”. I plan to do:
S&P 500 Index Fund 60% - 0.02% Expense Ratio
International Equity Index 30% - 0.04% Expense Ratio
Investment Grade Bond Index 10% - 0.03% Expense Ratio

My questions are:
Should I try and approximate the total market by adding some small and large company index funds? And if so, how much is appropriate?
Will I incur any fees while reallocating my funds?
How will the expense ratio be calculated for my new asset allocation?
And am I going about this the right way? Any critiques are welcome.