Hello! My team had some similar issues earlier on. You've probably moved on by now, but this might help if you have not altered your design by now.
1) Both the iPhone 5 and MacBook Pro (if late 2013 or later) have BT 4.0 compatibility. My team got a 4.0 compatible computer to recognize our BTLE device, but it did not connect at any point. The most likely issue is on the software side of the TinyDuino.
2) Yes. Unless your power budget is low, going to classic Bluetooth gives greater range, is less taxing on the processor, and it is overall much easier to deal with.
3) Definitely. Although not easy (my team has run into some connectivity issues dealing with data transmission rates not necessarily lining up with what they should, in a perfect world, be), it is certainly possible to do so.