My whole objective with edibles has been similar to what you are going for -- small, shelf-stable, stealthy, and potent. Here are the two things that have worked the best for me so far:
1) If you are going the coconut oil route, capsules are obviously the way to go. Sort of a waste of fresh herb since ABV works just as well, but capsules are very stealthy provided they are not transparent...I use
these which has earned them the nickname "Green Bay Packers". If warm weather oil can get melty... I've never had a problem but I always store mine in the freezer just to be safe. Better for long-term storage too so the oil doesn't go rancid.
2) The other option is butter caramels. Obviously this requires butter and not oil. I messed around with a lot of caramel recipes...
this recipe from Land O'Lakes is far and away the best. Its the best because it has a relatively high proportion of butter so its more concentrated, and because unlike other recipes I've seen you are only taking the caramels up to 244F. This is good because 1) when you take the temp higher there is the risk of degrading or burning off THC and 2) its easy to burn the caramel if you dont watch the temp closely. You need a good thermometer for this - I recommend you get a digital instant read if you can and take the temp up slowly. If you make caramels the size that are the recipe photo, that will give you a solid dose provided you use good, strong butter. For an extra layer of stealth, I have been known to cut the caramels in smaller squares, then dip them in chocolate. Then buy a small gift box of chocolate, swap the chocolates out with the ones you just made, and you are good to go.
For only 3.5g of bud, careful not to use too much butter. Even for the caramels, you could use some ABV to top up the recipe and they will turn out fine. I make em with ABV only and the sugar does a good job of making the ABV taste more palatable.
Let us know how it turns out...
I bake the firecracker at 320 for 20, but it also still tastes like butt. 