Mobile App patent (rejectable)?

If the technology is being used in other apps, it will be necessary to determine if the technology is patentable, novel, and non-obvious in light...

After doing a complete prior art search and determining exactly what these (as well as other published patents) cover you can then work on...

Yes without getting approval by the owner of the TM you will be infringing. Your best bet is to not use the TM or to contact the TM owner and talk...

Do I need a lawyer for rectifying a problem with an ePCT patent application?

There are many factors at play here and you will want a Patent Attorney who has experience with PCT filings to review everything and let you know...