1. Because it isn't in their interest. Plus between the time of your interview, assessment, TR, OCC and then Line Training many things develop, change and progress. 24 hours is a long time in Ryanair. Circumstances and requirements change daily.
2. There is never any rymme nor reason to what bases need FOs. One base which is chocked to the gunnels with crew and is known and reported to have little or no movement can have 5 FOs added to it in a space of a day. Makes no difference. They will be on BRK contracts and will only be paid when they fly - whether that be 30 hours or 100 hours a month.
3. Can't answer that one. However I would say Ryanair will want you to step up to the plate if their current desire for Cpts continue. You will need to have operated for one winter season on the 738 and accumulate 500 hrs on type (as already stated).
4. The rumour mill is awash - don't know how much is true. PSR in Italy will be the 31st base (or is it 32?? - maybe 30 if NRN goes - although we all hope that it doesn't for the sake of our colleagues). Other rumours have been CPH, AGP, OPO, FAO, KRK. I even heard rumours that they were wanting to move the PIK aircraft to GLA. You just dont know. However FR are always looking into new bases - they have to, the delivery program from Seattle is long!