The safe dose of excel depends on fauna you have in the aquarium, do you have shrimps ? Some plants are also not very tolerant to excel, eg vals.
I used 2x-3x the recommended dose of EasyCarbo with no adverse observed effects. Stop the filter and with a syringe put Excel over the affected area. Start your filter after 5-10 minutes.
The second one looks indeed like a filamentous green algae, like cladophora. It too can be treated with excel.
I don't know how one would spray hydrogen peroxide on an algae that grows at substrate level and would presumably be covered with water.
Keep in mind excel treatment will remove the algae but unless you deal with the reason why it appeared in the first place, you will have to do this every 2 weeks or so.
I would say the reason is high organics or low plant health...I had a similar experience with staghorn taking over one part of a wood I just introduced. It was fun to see how the algae was growing only in the area that still had some bark left..
On hiatus till later this year