First, happy dance that your HSA offers not just one but multiple low cost mutual funds. Also, you are offered share classes, admiral or institutional, that are the lowest offered by Vanguard.
Second, you have a nice mix here. Something that you can create diversification if this is your only investment vehicle. If you have other investments, consider that in your overall decision.
Here are the fund names in case that helps others with their response.
- VSMAX - small cap index admiral shares
- VIIIX - institutional index institutional shares
- VIGIX - growth index institutional shares
- VEMPX - extended market institutional shares
- VGSNX - reit index institutional shares
I think we will need more information about your personal investing plan to offer advice tailored to your specific need. Can you share your personal plan including risk tolerance, time horizon, other existing investments, etc?