This will cause no problem for periods up to
6 months, as a general rule (§ 51(1)(7) AufenthG)
12 months, for EU Blue Card holders (§ 51 (10) AufenthG)
For any longer period, permission must be granted by the foreigners authority.
Section 51 AufenthG
Termination of lawful residence; continued validity of restrictions
(1) The residence title shall ...
Yes, as a resident of the United Kingdom, you can apply for a Schengen Visa from within the United Kingdom.
Note that different consulates may be responsible based on the area within the United Kingdom that you reside.
According to Schengen rules, applicants have to apply for a visa in the Counslate of the country which can be identified as the main ...
Since you have a valid Schengen Visa, that can be used until it becomes invalid.
If the issuing conditions were based on the validity of your UK BRP, then the Schengen Visa validity would would be the same as the BRP.
When actually entering the Schengen Area, the border guard (independent of visa validity) will make the final decision if you may enter or ...