On your first question, you’re going to get different answers on TSP versus Roth contributions. My advice is place the first 5% in your TSP account to get the maximum government match. Then fund the Roth IRA, and work on savings a few months living expenses in emergency fund for unforeseen events. If you have any money left after that, open a taxable account at mutual fund or low cost brokerage. Invest in low cost index funds. You should have investments in all three types of accounts (TSP, Roth, Taxable). Its just wise money management to spread your future tax risk among low-tax (taxable accounts), higher tax (TSP), and tax-free (Roth) accounts. Only after funding all three, would I consider putting additional funds in your TSP. That very well could happen as you near your retirement date and your wages/assets increase. Of course this is just my opinion which is based upon personal experience over last twenty years.
If you are a highly paid worker you may have to place more than 5% in your TSP account to get your adjusted gross income below the $95,000 (single) or $150,000 (married joint) Roth thresholds. Otherwise, you would not be able to contribute the full amount allowed. This was my issue the last few years I worked before retirement. Another consideration that impacts most government workers is the cost of raising a family precludes setting aside much more that 10% for retirement. The cost of living makes it difficult to put the maximum $15,500 into TSP AND then fund the Roth IRA. That is just not an reasonable expectation.
On the second question both L2040 and L2030 are more conservative (i.e. less in stock funds) than your current allocation. The L2040 fund has 84.5% in C/S/I funds and the L2030 fund has about 74.5% in C/S/I. The year of the Lifecycle fund matures is the year that it moves into a 20% allocation among C/S/I funds. This is too conservative in my opinion. If I were your age I would choose L2040. But, once again that is just my opinion.
Also important is paying for post-56 military time to get the credit for FERS retirement. The interest starts accumulation on money owed after three years of employment. The government uses the G fund rate for the interest charge (5-6%). I waited more that ten years before paying for my 10+ years of post-56 military time, and the amount owed went from $6,400 to $11,000 in course of twelve years. The first five years or so had interest rates of 9% to 13%. The important action to take now is getting the estimated military earnings. Then apply to repay the amount through paycheck withdrawals. It can be spread over years so it won’t hurt much.