We are a young startup, founded by 3 members about a year and a half ago, and recently closed a seed-stage investment round.
We are about to hire our first 3 employees, 2 tech, 1 business-development.
How much should I give each?
Given few will get more or less, the very same they would have get in their current job, how does this fact shall affect the package size?
How much shall I secure for future / upcoming hiring?
Don't just think in terms of how much equity to give but also in terms of the vesting schedule.
You'll find countless questions on this site about startups that gave equity upfront and that ended up regretting it. My recommendation: agree upfront on an amount but then nothing actually starts vesting before a trial period of 6-12 months. I think a vesting schedule of 3-5 years, depending on the amount, would seem reasonable. You'll just have to figure out how much to give your recruits.
No matter what, don't botch the vesting schedule!