These should really be growing outdoors - the only reason they're so tall is because of insufficient light. Chives like full sun if possible, and outdoors if possible.
In regard to separating the 4 bulbs you've got, no, don't do that, and the pot is more than big enough for the small amount of chives you have. Leave them in their pot until they've multiplied to almost fill the soil in the pot, which will probably be in a couple of years, but they will do much better out of doors if that's possible.
You can snip some for use now if you like, but if you want your bulbs to multiply, and you do, it would be better to just take the tips off for use, but don't cut too much this year. You can eat the flowers on chives, but the flowered stems are tough and unpleasant to eat.
I'm also not sure about drying them; what usually happens is, just before the foliage dies down in autumn (if outdoors), its usual to cut them down, then snip the stems into short lengths and put portions in foil packets, put the packets inside a plastic bag and freeze them, so you can remove a portion at a time for use over winter. Snippings can be made during the growing season for use in the kitchen too - but you've only got 4 bulbs,and constantly removing the foliage during the growing season means the bulbs can't store food for next year, so it would be best to leave them alone till they've multiplied next year, depending how well they do.