various technical questions

Here's the answer to one of your 5 questions:

2. I will travel to Spain mid-november with the family I am staying with and would like to stay there until January, can I stay up to 90 days even though a complete 6 months has not passed since I left Germany past June?

Here's the rule that applies to Germany and Spain but not Ireland: The total number of days spent in the Schengen zone (which includes Spain and Germany) cannot exceed 90 days during the 6 months following the date of first entry.

The 6 months starts running from the date of first entry into the Schengen zone. You can stay in the Schengen zone a maximum of 90 days in the 6 months following date of first entry into the Schengen zone. You can enter and leave multiple times during that 6-month period, as long as the total time in the Schengen zone (25 countries but not including Ireland and the UK) does not exceed 90 days per 6-month period.

Since these are very specific immigration and visa questions, it would be best if you contacted the Irish Embassy. Have you read the requirements for an Irish student visa online? For a holiday visa? They will also answer many of your questions, for example they indicate you will have to submitted your previous passports when applying fora student visa. In addition, the school where you are completing your studies should be able to help you with these matters as well.

http://www.embassyofireland.org/home/index.aspx?id=30782

1) Yes

2) Yes...as Kent mentioned the six months started the day of first entry into Schengen which was April 8th

3) You can renew a passport at any time.

4) Probably... but it won't matter since you will be re-entering six months after your first visit

5) No...90 days within a six month period...if you stay 90 days from August to November....you won't be allowed to re-enter Ireland until six months after your first entry into Ireland.

However, keep in mind, how long you can stay is up to the immigration officer upon arrival in Ireland. If he feels you are there to work, or you can't show proof that you can support yourself during your stay, he may not allow you the full 90 days.

To elaborate on #2 for your specific circumstance:

You essentially have 36 days still left in the six month period starting April 8, If you were to return prior to November 8, as long as you do not spend more than the 36 days there prior to November 8, you are fine. Since you will not be returning it sounds prior to November 8, you will have a full 90 days.

As for a Student Visa, I think I would work out the details now via the Irish Embassy. It is not automatic, nor something that is just filling out paperwork and waiting to hear. Two critical requirements are a formal final letter of acceptance issued by the school after you have paid tuition in full; and documentation showing your means of support, typically bank account information, income sources, etc.