If I understand your post, you:
1) have removed all the old finish, 2) want to stain chairs a robin's egg blue, but 3) want the blue to be relatively easy to remove, if your tastes change in a few years. If this is the case, there's a couple things you can try.
The first thing is that you don't want the blue to penetrate into the wood - rather to sit on top of the wood. There's nothing wrong with this approach - furniture mfgr's do it all the time. To accomplish this you can choose from either of the techniques below.
1) Seal with shellac: Apply a coat of SealCoat to all surfaces. Sealcoat is a diluted shellac, that will penetrate the wood. Both water and oil base products adhere to shellac. Once you've applied, light sand all surfaces and vacuum up dust. You can now apply either a pigment stain or a dye stain. Dye stains are translucent, while pigment stains are more opaque. Apply the stain to a test area, and before it dries, decide if you like the look. If so, let it dry. If not remove the stain with the appropriate solvent (water or paint thinner). The stain is sitting on the shellac, so it will wipe off easily, and you can test another stain type or mix. Once you decide on the color/type of stain, let it dry, and apply a couple coats of finish.
2) MIx some stain into your finish: For this technique you need spray equip. You can try brushing but it usually doesn't turn out as well. For this, you can seal with shellac (as above), or proceed without the sealcoat. You will have to experiment with a bunch of different dilutions of stain to get the right color. Test the dilutions on an inconspicuous spot, like the underside of a chair. Once you have it right, apply to all surfaces, let dry, and then apply a couple coats of finish.
With both techniques, removing the color is going to be relatively easy, because the stain isn't in the wood, rather in the finish. You can sand or strip it off easily. Once removed, you can either leave the shellac on, remove it (wipe down all surfaces with a rag dipped in ammonia), or add another coat.
This should steer you in the right direction
Bob "Boardman" Borders