Yes, the R7 260 can run this.
Yes, the R7 260 can run this.
No site displays a graph covering all GPU benchmarks to my knowledge.
Already shared a reference link: http://www.videocardbenchmark.net/ 3DMark also offers comparable resources if you search for that. In reality, the most useful comparisons are usually between cards released just a few years prior. Anything else will be artificial and not very meaningful. Comparing older games to newer ones doesn't engage anyone since high-end cards no longer stand out. Likewise, using old card data with modern titles loses relevance because those cards aren't widely available anymore.