As I recall, the Irish people resisted EU membership but were shoved in anyway. I don't know if that is the case for the other satellite countries like Portugal and Greece. The reason I bring this up is because of the possibility these less affluent countries imagined they were going to benefit from having a financial share among more affluent members like Germany.
In other words, their native contributions would stay weak as usual but they would benefit anyways from having an EU bond with the more productive neighboring economies. So, they thought they were going to game the system a little in their favor but instead the shrewd German bankers not only turned the tables but helped draw the viability of the union itself into serious question.
Yes and no. You are absolutely right that the small nations on the periphery of Europe expected to gain wealth from the Eurozone. Also remember that the problem is not the people, but their leaders. In Ireland as you say, the people voted down the full integration, but were bombarded with corporate propaganda (largely funded privately by Intel) and made to vote again. It was made explicitly clear by policy makers that the state would continue to hold referenda until the people voted 'yes'.
The world crash was characterised and explained by one single phrase:
short-termism. Everybody cashed in their chips today, ignoring the fact that they would have to pay out more tomorrow.
In the small EU economies (Cyprus, Estonia, Slovakia, Slovenia) the result was a ludicrous housing bubble that has still not yet unwound. And other states hoping to get in on the activity (Bulgaria, Serbia, Montenegro) are now being described as the new places for property speculators to go to avoid the inevitable bankruptcy ruling snapping at their heels. But a bubble will always deflate, and regular people will be mugged by the corrupt insiders who know when to withdraw their money from the game.
In the larger economies where corruption is endemic, (Italy, Spain, Portugal, Greece) the property market was again the one used by money launderers, speculators and private wealth kleptocrats to syphon off money collected as taxes into private pockets. In these cases it was largely (but not always) the construction side of the industry that was the basis for activities (Silvio Berlusconi has already openly spoken about his early career in the construction industry, and how he was unable to avoid doing business with organised crime simply because they ran the entire industry).
In Great Britain there is a simple case study in the mismanaged bank HBOS. from 2006-2007, HBOS invested in McCarthy&Stone, Crest Nicholson, Kilmartin, and Miller, all of which are construction and property developers. The bank was pouring money into the housing market and into private hands whilst the markets were collapsing. Now the British government has pledged the peoples' tax money to the bank because it has run out of money.
The Irish example is slightly different from the other PIIGs thanks to the Intel/USA connection. America pumped in large amounts of cash for development into Ireland in the form of business contracts. Intel based a large operation there. The reason for this was a specific objective which is an interesting mix of economic theory and computer technology: they wanted to build a trading hub for Wall Street in Dublin. In the modern age of stocks and shares being traded automatically by computers
("flash trades") then a factor as small as the length of fibre optic cable can allow you to get a better price, as you are effectively jumping the queue. So America wanted to launch a financial service hub in Dublin to trade in the Eurozone, and using EU-backed regulation which allows access to certain trades and markets that the USA does not recognise as legitimate. Ireland would have seen a decent kickback from this, but as we have all seen, the plan was never in their own long-term interest.