Welcome!

Glads can be planted anytime all danger of frost has passed and the soil has warmed up a bit. I'd wait a bit in your location, but perhaps someone from that area will jump in and offer local advice. Depending upon the size of the corm, plant 3 to 5 inches deep.

The problem with sowing seeds is that you have to wait so long to sow them and the spacing is so difficult. Think of your little pile of 300 seeds, and then compare that to 300 plants, already grown and ready to stick in the ground! It's almost impossible to sow seeds in situ and place each seed 6 or 8 or 12 inches apart. If seeds are sown, then we always end up thinning the heck out of them.

I never sow seeds directly anymore, and haven't for many years, so am not a good one to advise you. I will tell you that Portulaca seeds are miniscule, and even when seeding into a flat, they should be mixed with corn meal or grits to aid in spreading them out. They should not be buried, but prefer sunlight in order to germinate.

I'm not sure what the base allows you to do. You would have to check with the base housing office for that info.
We have a booklet that people advertise for free called The Bulletin Board that you can buy at the BX and new ones come out each Thursday. Look in the Lawn and Garden section. People sometimes advertise plants for free if you will come get them or dig them up. Some sell plants. You can place an ad for free asking for plants.
The BX has some bulbs for a reasonable price but the plants are higher than other places and not in the best condition. You would have to just check them out.
My plants are just starting to come up. I do not have the plants you mentioned. Is there any other plants you are interested in?
Lynn in Prattville.