General Enhancer Questions (Methylation Patterns, ect.)
This subject is actually both complicated and incompletely understood. For example, there is evidence that some enhancers don't result in loops at all — instead their influence travels along the chromatin to a nearby promoter. 

You can think of enhancers as being staging areas where protein complexes that promote transcription are assembled. In some cases enhancers are where the RNA polymerase complex is first bound. 

When loops do form, this allows the proteins at an enhancer to interact directly with the transcriptional start site.

I think you will find this 2015 review to be a helpful introduction.1



As for methylation (which maybe would be better as a separate question), it is generally true that methylation acts to reduce transcription factor binding and thus decreases transcription.2

However, that overall trend disguises some more complex dynamics.3



References:
1: Pennacchio, L. A., Bickmore, W., Dean, A., Nobrega, M. A., &amp; Bejerano, G. (2013). Enhancers: five essential questions. Nature Reviews Genetics, 14(4), 288.
2: Lea, A. J., Vockley, C. M., Johnston, R. A., Del Carpio, C. A., Barreiro, L. B., Reddy, T. E., &amp; Tung, J. (2018). Genome-wide quantification of the effects of DNA methylation on human gene regulation. ELife, 7, e37513.
3: Sharifi-Zarchi, A., Gerovska, D., Adachi, K., Totonchi, M., Pezeshk, H., Taft, R. J., ... &amp; Araúzo-Bravo, M. J. (2017). DNA methylation regulates discrimination of enhancers from promoters through a H3K4me1-H3K4me3 seesaw mechanism. BMC genomics, 18(1), 964.